Publications by authors named "Thomas J Hope"

142 Publications

SIV susceptibility, immunology and microbiome in the female genital tract of adolescent versus adult pigtail macaques.

AIDS Res Hum Retroviruses 2021 Jan 15. Epub 2021 Jan 15.

University of Minnesota System, 311816, Department of Medicine, Minneapolis, Minnesota, United States;

In Sub-Saharan Africa, young women aged 15-24 account for nearly 30% of all new HIV infections, however biological and epidemiological factors underlying this disproportionate infection rate are unclear. Here, we assessed biological contributors of SIV/HIV susceptibility in the female genital tract (FGT) using adolescent (n=9) and adult (n=10) pigtail macaques (PTMs) with weekly low-dose intravaginal challenges of SIV. Immunological variables were captured in vaginal tissue of PTMs by flow cytometry and cytokine assays. Vaginal biopsies were profiled by proteomic analysis. The vaginal microbiome was assessed by 16S rRNA sequencing. We were powered to detect a 2.2-fold increase in infection rates between age groups, however we identified no significant differences in susceptibility. This model cannot capture epidemiological factors or may not best represent biological differences of HIV susceptibility. No immune cell subsets measured were significantly different between groups. Inflammatory marker MCP-1 was significantly higher (adj p=0.02), and sCD40L trended higher (adj p=0.06) in vaginal cytobrushes of adults. Proteomic analysis of vaginal biopsies showed no significant (adj p<0.05) protein or pathway differences between groups. Vaginal microbiomes were not significantly different between groups. No differences were observed between age groups in this PTM model, however these animals may not reflect biological factors contributing to HIV risk such as those found in their human counterparts. This model is therefore not appropriate to explore human adolescent differences in HIV risk. Young women remain a key population at risk for HIV infection, and there is still a need for comprehensive assessments and interventions strategies for epidemic control of this uniquely vulnerable population.
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http://dx.doi.org/10.1089/AID.2020.0271DOI Listing
January 2021

Design and Testing of a Cabotegravir Implant for HIV Prevention.

J Control Release 2021 Feb 19;330:658-668. Epub 2020 Dec 19.

Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA. Electronic address:

Long-acting antiretroviral implants could help protect high-risk individuals from HIV infection. We describe the design and testing of a long-acting reservoir subcutaneous implant capable of releasing cabotegravir for several months. We compressed cabotegravir and excipients into cylindrical pellets and heat-sealed them in tubing composed of hydrophilic poly(ether-urethane) -. The implants have a 47 mm lumen length, 3.6 mm outer diameter, and 200 μm wall thickness. Four cabotegravir pellets were sealed in the membrane, with a total drug loading of 274 ± 3 mg. In vivo, the implants released 348 ± 107 μg/day (median value per implant, N = 41) of cabotegravir in rhesus macaques. Five implants generated an average cabotegravir plasma concentration of 373 ng/ml in rhesus macaques. The non-human primates tolerated the implant without gross pathology or microscopic signs of histopathology compared to placebo implants. Cabotegravir plasma levels in macaques dropped below detectable levels within two weeks after the removal of the implants.
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http://dx.doi.org/10.1016/j.jconrel.2020.12.024DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7906957PMC
February 2021

Deep Gene Sequence Cluster Analyses of Multi-Virus-Infected Mucosal Tissue Reveal Enhanced Transmission of Acute HIV-1.

J Virol 2021 Jan 13;95(3). Epub 2021 Jan 13.

Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada

Exposure of the genital mucosa to a genetically diverse viral swarm from the donor HIV-1 can result in breakthrough and systemic infection by a single transmitted/founder (TF) virus in the recipient. The highly diverse HIV-1 envelope (Env) in this inoculating viral swarm may have a critical role in transmission and subsequent immune response. Thus, chronic (Env) and acute (Env) Env chimeric HIV-1 were tested using multivirus competition assays in human mucosal penile and cervical tissues. Viral competition analysis revealed that Env viruses resided and replicated mainly in the tissue, while Env viruses penetrated the human tissue and established infection of CD4 T cells more efficiently. Analysis of the replication fitness, as tested in peripheral blood mononuclear cells (PBMCs), showed similar replication fitness of Env and Env viruses, which did not correlate with transmission fitness in penile tissue. Further, we observed that chimeric Env viruses with higher replication in genital mucosal tissue (chronic Env viruses) had higher binding affinity to C-type lectins. Data presented herein suggest that the inoculating HIV-1 may be sequestered in the genital mucosal tissue (represented by chronic Env HIV-1) but that a single HIV-1 clone (e.g., acute Env HIV-1) can escape this trapped replication for systemic infection. During heterosexual HIV-1 transmission, a genetic bottleneck occurs in the newly infected individual as the virus passes from the mucosa, leading to systemic infection with a single transmitted HIV-1 clone in the recipient. This bottleneck in the recipient has just been described (K. Klein et al., PLoS Pathog 14:e1006754, https://doi.org/10.1371/journal.ppat.1006754), and the mechanisms involved in this selection process have not been elucidated. However, understanding mucosal restriction is of the utmost importance for understanding dynamics of infections and for designing focused vaccines. Using our human penile and cervical mucosal tissue models for mixed HIV infections, we provide evidence that HIV-1 from acute/early infection, compared to that from chronic infection, can more efficiently traverse the mucosal epithelium and be transmitted to T cells, suggesting higher transmission fitness. This study focused on the role of the HIV-1 envelope in transmission and provides strong evidence that HIV transmission may involve breaking the mucosal lectin trap.
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http://dx.doi.org/10.1128/JVI.01737-20DOI Listing
January 2021

Correlated cryogenic fluorescence microscopy and electron cryo-tomography shows that exogenous TRIM5α can form hexagonal lattices or autophagy aggregates in vivo.

Proc Natl Acad Sci U S A 2020 11 5;117(47):29702-29711. Epub 2020 Nov 5.

Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125;

Members of the tripartite motif (TRIM) protein family have been shown to assemble into structures in both the nucleus and cytoplasm. One TRIM protein family member, TRIM5α, has been shown to form cytoplasmic bodies involved in restricting retroviruses such as HIV-1. Here we applied cryogenic correlated light and electron microscopy, combined with electron cryo-tomography, to intact mammalian cells expressing YFP-rhTRIM5α and found the presence of hexagonal nets whose arm lengths were similar to those of the hexagonal nets formed by purified TRIM5α in vitro. We also observed YFP-rhTRIM5α within a diversity of structures with characteristics expected for organelles involved in different stages of macroautophagy, including disorganized protein aggregations (sequestosomes), sequestosomes flanked by flat double-membraned vesicles (sequestosome:phagophore complexes), sequestosomes within double-membraned vesicles (autophagosomes), and sequestosomes within multivesicular autophagic vacuoles (amphisomes or autolysosomes). Vaults were also seen in these structures, consistent with their role in autophagy. Our data 1) support recent reports that TRIM5α can form both well-organized signaling complexes and nonsignaling aggregates, 2) offer images of the macroautophagy pathway in a near-native state, and 3) reveal that vaults arrive early in macroautophagy.
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http://dx.doi.org/10.1073/pnas.1920323117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7703684PMC
November 2020

Timothy Ray Brown: The Serendipitous Hero of HIV Cure Research.

AIDS Res Hum Retroviruses 2020 11;36(11):883-885

Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.

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http://dx.doi.org/10.1089/AID.2020.0253DOI Listing
November 2020

Recommendations for measuring HIV reservoir size in cure-directed clinical trials.

Nat Med 2020 09 7;26(9):1339-1350. Epub 2020 Sep 7.

The Wistar Institute, Philadelphia, PA, USA.

Therapeutic strategies are being clinically tested either to eradicate latent HIV reservoirs or to achieve virologic control in the absence of antiretroviral therapy. Attaining this goal will require a consensus on how best to measure the numbers of persistently infected cells with the potential to cause viral rebound after antiretroviral-therapy cessation in assessing the results of cure-directed strategies in vivo. Current measurements assess various aspects of the HIV provirus and its functionality and produce divergent results. Here, we provide recommendations from the BEAT-HIV Martin Delaney Collaboratory on which viral measurements should be prioritized in HIV-cure-directed clinical trials.
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http://dx.doi.org/10.1038/s41591-020-1022-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7703694PMC
September 2020

Entry of glucose- and glutamine-derived carbons into the citric acid cycle supports early steps of HIV-1 infection in CD4 T cells.

Nat Metab 2019 07 12;1(7):717-730. Epub 2019 Jul 12.

Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France.

The susceptibility of CD4 T cells to human immunodeficiency virus 1 (HIV-1) infection is regulated by glucose and glutamine metabolism, but the relative contributions of these nutrients to infection are not known. Here we show that glutaminolysis is the major pathway fuelling the tricarboxylic acid (TCA) cycle and oxidative phosphorylation (OXPHOS) in T-cell receptor-stimulated naïve, as well as memory CD4, subsets and is required for optimal HIV-1 infection. Under conditions of attenuated glutaminolysis, the α-ketoglutarate (α-KG) TCA rescues early steps in infection; exogenous α-KG promotes HIV-1 reverse transcription, rendering both naïve and memory cells more sensitive to infection. Blocking the glycolytic flux of pyruvate to lactate results in altered glucose carbon allocation to TCA and pentose phosphate pathway intermediates, an increase in OXPHOS and augmented HIV-1 reverse transcription. Moreover, HIV-1 infection is significantly higher in CD4 T cells selected on the basis of high mitochondrial biomass and OXPHOS activity. Therefore, the OXPHOS/aerobic glycolysis balance is a major regulator of HIV-1 infection in CD4 T lymphocytes.
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http://dx.doi.org/10.1038/s42255-019-0084-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7199465PMC
July 2019

Understanding the Acceptability of Subdermal Implants as a Possible New HIV Prevention Method: Multi-Stage Mixed Methods Study.

J Med Internet Res 2020 07 27;22(7):e16904. Epub 2020 Jul 27.

Feinberg School of Medicine, Northwestern University, Chicago, IL, United States.

Background: A long-acting implant for HIV pre-exposure prophylaxis (PrEP) is in development in the Sustained Long-Action Prevention Against HIV (SLAP-HIV) trial. This could provide an alternative to oral PrEP.

Objective: Our mixed methods study aimed to understand (1) users' experiences with a similar subdermal implant for contraception and (2) factors influencing the likelihood that gay and bisexual men (GBM) would use a proposed PrEP implant.

Methods: Work was completed in 4 stages. In stage 1, we conducted a scientific literature review on existing subdermal implants, focusing on users' experiences with implant devices. In stage 2, we reviewed videos on YouTube, focusing on the experiences of current or former contraceptive implant users (as these implants are similar to those in development in SLAP-HIV). In stage 3, individuals who indicated use of a subdermal implant for contraception in the last 5 years were recruited via a web-based questionnaire. Eligible participants (n=12 individuals who liked implants a lot and n=12 individuals who disliked implants a lot) completed in-depth phone interviews (IDIs) about their experiences. In stage 4, results from IDIs were used to develop a web-based survey for HIV-negative GBM to rate their likelihood of using a PrEP implant on a scale (1=very unlikely and 5=very likely) based on likely device characteristics and implant concerns identified in the IDIs.

Results: In the scientific literature review (stage 1), concerns about contraceptive implants that could apply to the PrEP implants in development included potential side effects (eg, headache), anticipated high cost of the device, misconceptions about PrEP implants (eg, specific contraindications), and difficulty accessing PrEP implants. In the stage 2 YouTube review, individuals who had used contraceptive implants reported mild side effects related to their device. In stage 3, implant users reported that devices were comfortable, unintrusive, and presented only minor discomfort (eg, bruising) before or after insertion and removal. They mainly reported removing or disliking the device due to contraceptive-related side effects (eg, prolonged menstruation). Participants in the stage 4 quantitative survey (N=304) were mainly gay (204/238, 85.7%), white (125/238, 52.5%), cisgender men (231/238, 97.1%), and 42.0% (73/174) of them were on oral PrEP. Not having to take a daily pill increased the likelihood of using PrEP implants (mean 4.13). Requiring >1 device to achieve 1 year of protection (mean range 1.79-2.94) mildly discouraged PrEP implant use. Participants did not mind moderate bruising, a small scar, tenderness, or bleeding after insertion or removal, and an implant with a size slightly larger than a matchstick (mean ratings 3.18-3.69).

Conclusions: PrEP implants are promising among GBM. Implant features and insertion or removal-related concerns do not seem to discourage potential users. To ensure acceptability, PrEP implants should require the fewest possible implants for the greatest protection duration.
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http://dx.doi.org/10.2196/16904DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7418007PMC
July 2020

Visualizing Association of the Retroviral Gag Protein with Unspliced Viral RNA in the Nucleus.

mBio 2020 04 7;11(2). Epub 2020 Apr 7.

Department of Medicine, Penn State College of Medicine, Hershey, Pennsylvania, USA

Packaging of genomic RNA (gRNA) by retroviruses is essential for infectivity, yet the subcellular site of the initial interaction between the Gag polyprotein and gRNA remains poorly defined. Because retroviral particles are released from the plasma membrane, it was previously thought that Gag proteins initially bound to gRNA in the cytoplasm or at the plasma membrane. However, the Gag protein of the avian retrovirus Rous sarcoma virus (RSV) undergoes active nuclear trafficking, which is required for efficient gRNA encapsidation (L. Z. Scheifele, R. A. Garbitt, J. D. Rhoads, and L. J. Parent, Proc Natl Acad Sci U S A 99:3944-3949, 2002, https://doi.org/10.1073/pnas.062652199; R. Garbitt-Hirst, S. P. Kenney, and L. J. Parent, J Virol 83:6790-6797, 2009, https://doi.org/10.1128/JVI.00101-09). These results raise the intriguing possibility that the primary contact between Gag and gRNA might occur in the nucleus. To examine this possibility, we created a RSV proviral construct that includes 24 tandem repeats of MS2 RNA stem-loops, making it possible to track RSV viral RNA (vRNA) in live cells in which a fluorophore-conjugated MS2 coat protein is coexpressed. Using confocal microscopy, we observed that both wild-type Gag and a nuclear export mutant (Gag.L219A) colocalized with vRNA in the nucleus. In live-cell time-lapse images, the wild-type Gag protein trafficked together with vRNA as a single ribonucleoprotein (RNP) complex in the nucleoplasm near the nuclear periphery, appearing to traverse the nuclear envelope into the cytoplasm. Furthermore, biophysical imaging methods suggest that Gag and the unspliced vRNA physically interact in the nucleus. Taken together, these data suggest that RSV Gag binds unspliced vRNA to export it from the nucleus, possibly for packaging into virions as the viral genome. Retroviruses cause severe diseases in animals and humans, including cancer and acquired immunodeficiency syndromes. To propagate infection, retroviruses assemble new virus particles that contain viral proteins and unspliced vRNA to use as gRNA. Despite the critical requirement for gRNA packaging, the molecular mechanisms governing the identification and selection of gRNA by the Gag protein remain poorly understood. In this report, we demonstrate that the Rous sarcoma virus (RSV) Gag protein colocalizes with unspliced vRNA in the nucleus in the interchromatin space. Using live-cell confocal imaging, RSV Gag and unspliced vRNA were observed to move together from inside the nucleus across the nuclear envelope, suggesting that the Gag-gRNA complex initially forms in the nucleus and undergoes nuclear export into the cytoplasm as a viral ribonucleoprotein (vRNP) complex.
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http://dx.doi.org/10.1128/mBio.00524-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7157774PMC
April 2020

Barriers of Mucosal Entry of HIV/SIV.

Curr Immunol Rev 2019 ;15(1):4-13

Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Lurie 9-290, Chicago, IL 60611, USA.

Most new HIV infections, over 80%, occur through sexual transmission. During sexual transmission, the virus must bypass specific female and male reproductive tract anatomical barriers to encounter viable target cells. Understanding the generally efficient ability of these barrier to exclude HIV and the precise mechanisms of HIV translocation beyond these genital barriers is essential for vaccine and novel therapeutic development. In this review, we explore the mucosal, barriers of cervico-vaginal and penile tissues that comprise the female and male reproductive tracts. The unique cellular assemblies f the squamous and columnar epithelium are illustrate highlighting their structure and function. Each anatomical tissue offers a unique barrier to virus entry in healthy individuals. Unfortunately barrier dysfunction can lead to HIV transmission. How these diverse mucosal barriers have the potential to fail is considered, highlighting those anatomical areas that are postulated to offer a weaker barrier and are; therefore, more susceptible to viral ingress. Risk factors, such as sexually transmitted infections, microbiome dysbiosis, and high progestin environments are also associated with increased acquisition of HIV. How these states may affect the integrity of mucosal barriers leading to HIV acquisition are discussed suggesting mechanisms of transmission and revealing potential targets for intervention.
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http://dx.doi.org/10.2174/1573395514666180604084404DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6919325PMC
January 2019

Longitudinal bioluminescent imaging of HIV-1 infection during antiretroviral therapy and treatment interruption in humanized mice.

PLoS Pathog 2019 12 5;15(12):e1008161. Epub 2019 Dec 5.

Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, United States of America.

Non-invasive bioluminescent imaging (NIBLI) of HIV-1 infection dynamics allows for real-time monitoring of viral spread and the localization of infected cell populations in living animals. In this report, we describe full-length replication-competent GFP and Nanoluciferase (Nluc) expressing HIV-1 reporter viruses from two clinical transmitted / founder (T/F) strains: TRJO.c and Q23.BG505. By infecting humanized mice with these HIV-1 T/F reporter viruses, we were able to directly monitor longitudinal viral spread at whole-animal resolution via NIBLI at a sensitivity of as few as 30-50 infected cells. Bioluminescent signal strongly correlated with HIV-1 infection and responded proportionally to virus suppression in vivo in animals treated daily with a combination antiretroviral therapy (cART) regimen. Longitudinal NIBLI following cART withdrawal visualized tissue-sites that harbored virus during infection recrudescence. Notably, we observed rebounding infection in the same lymphoid tissues where infection was first observed prior to ART treatment. Our work demonstrates the utility of our system for studying in vivo viral infection dynamics and identifying infected tissue regions for subsequent analyses.
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http://dx.doi.org/10.1371/journal.ppat.1008161DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6917343PMC
December 2019

A MUC16 IgG Binding Activity Selects for a Restricted Subset of IgG Enriched for Certain Simian Immunodeficiency Virus Epitope Specificities.

J Virol 2020 02 14;94(5). Epub 2020 Feb 14.

Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA

We have recently shown that MUC16, a component of the glycocalyx of some mucosal barriers, has elevated binding to the G0 glycoform of the Fc portion of IgG. Therefore, IgG from patients chronically infected with human immunodeficiency virus (HIV), who typically exhibit increased amounts of G0 glycoforms, showed increased MUC16 binding compared to uninfected controls. Using the rhesus macaque simian immunodeficiency virus SIVmac251 model, we can compare plasma antibodies before and after chronic infection. We find increased binding of IgG to MUC16 after chronic SIV infection. Antibodies isolated for tight association with MUC16 (MUC16-eluted antibodies) show reduced FcγR engagement and antibody-dependent cellular cytotoxicity (ADCC) activity. The glycosylation profile of these IgGs was consistent with a decrease in FcγR engagement and subsequent ADCC effector function, as they contain a decrease in afucosylated bisecting glycoforms that preferentially bind FcγRs. Testing of the SIV antigen specificity of IgG from SIV-infected macaques revealed that the MUC16-eluted antibodies were enriched for certain specific epitopes, including regions of gp41 and gp120. This enrichment of specific antigen responses for fucosylated bisecting glycoforms and the subsequent association with MUC16 suggests that the immune response has the potential to direct specific epitope responses to localize to the glycocalyx through interaction with this specific mucin. Understanding how antibodies are distributed in the mucosal environment is valuable for developing a vaccine to block HIV infection. Here, we study an IgG binding activity in MUC16, potentially representing a new IgG effector function that would concentrate certain antibodies within the glycocalyx to trap pathogens before they can reach the underlying columnar epithelial barriers. These studies reveal that rhesus macaque IgG responses during chronic SIV infection generate increased antibodies that bind MUC16, and interestingly, these MUC16-tethered antibodies are enriched for binding to certain antigens. Therefore, it may be possible to direct HIV vaccine-generated responses to associate with MUC16 and enhance the antibody's ability to mediate immune exclusion by trapping virions within the glycocalyx and preventing the virus from reaching immune target cells within the mucosa. This concept will ultimately have to be tested in the rhesus macaque model, which is shown here to have MUC16-targeted antigen responses.
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http://dx.doi.org/10.1128/JVI.01246-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7022352PMC
February 2020

Transgender Women's Concerns and Preferences on Potential Future Long-Acting Biomedical HIV Prevention Strategies: The Case of Injections and Implanted Medication Delivery Devices (IMDDs).

AIDS Behav 2020 May;24(5):1452-1462

Northwestern University Feinberg School of Medicine, and Biomedical Engineering in the McCormick School of Engineering and Applied Sciences, Chicago, IL, USA.

There are several long-acting biomedical HIV prevention products in the development pipeline, including injections and implanted medication delivery devices (IMDDs). It is critical to understand concerns and preferences on the use of these products in populations that shoulder a disproportionate burden of the HIV epidemic, such as transgender women. This will allow researchers and public health professionals to construct interventions tailored to the needs of these women to promote optimal use of these tools. In studies of other biomedical HIV prevention products (e.g., oral PrEP) it is clear that transgender women have unique concerns related to the use of these strategies. This may have an impact on this group's uptake and sustained use of longacting HIV prevention products. This study conducted four focus groups with N = 18 transgender women in New York City to understand their concerns and preferences on long-acting PrEP injections and IMDDs. Findings showed that participants were overwhelmingly positive about long-acting HIV prevention strategies, though they had some apprehensions. Overall, participants felt that injections and IMDDs could help address adherence challenges, and that transgender-specific needs should be addressed during clinical trials. Also, there were concerns related to injection or IMDD logistics, concerns about injections' or IMDDs' presence in the body, and familiarity with these products affected participants' opinions on them. Findings from this work can be used to inform protocols, measures, materials, and adherence interventions in future initiatives for transgender women using PrEP injections or IMDDs.
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http://dx.doi.org/10.1007/s10461-019-02703-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7181384PMC
May 2020

Impact of chemokine C-C ligand 27, foreskin anatomy and sexually transmitted infections on HIV-1 target cell availability in adolescent South African males.

Mucosal Immunol 2020 01 16;13(1):118-127. Epub 2019 Oct 16.

Department of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.

We compared outer and inner foreskin tissue from adolescent males undergoing medical male circumcision to better understand signals that increase HIV target cell availability in the foreskin. We measured chemokine gene expression and the impact of sexually transmitted infections (STIs) on the density and location of T and Langerhans cells. Chemokine C-C ligand 27 (CCL27) was expressed 6.94-fold higher in the inner foreskin when compared with the outer foreskin. We show that the density of CD4CCR5 cells/mm was higher in the epithelium of the inner foreskin, regardless of STI status, in parallel with higher CCL27 gene expression. In the presence of STIs, there were higher numbers of CD4CCR5 cells/mm cells in the sub-stratum of the outer and inner foreskin with concurrently higher number of CD207 Langerhans cells (LC) in both tissues, with the latter cells being closer to the keratin surface of the outer FS in the presence of an STI. When we tested the ability of exogenous CCL27 to induce T-cell migration in foreskin tissue, CD4 + T cells were able to relocate to the inner foreskin epithelium in response. We provide novel insight into the impact CCL27 and STIs on immune and HIV-1 target cell changes in the foreskin.
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http://dx.doi.org/10.1038/s41385-019-0209-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6914668PMC
January 2020

Multiple Pathways To Avoid Beta Interferon Sensitivity of HIV-1 by Mutations in Capsid.

J Virol 2019 12 13;93(23). Epub 2019 Nov 13.

Research Institute for Microbial Diseases, Osaka University, Osaka, Japan

Type I interferons (IFNs), including alpha IFN (IFN-α) and IFN-β, potently suppress HIV-1 replication by upregulating IFN-stimulated genes (ISGs). The viral capsid protein (CA) partly determines the sensitivity of HIV-1 to IFNs. However, it remains to be determined whether CA-related functions, including utilization of known host factors, reverse transcription, and uncoating, affect the sensitivity of HIV-1 to IFN-mediated restriction. Recently, we identified an HIV-1 CA variant that is unusually sensitive to IFNs. This variant, called the RGDA/Q112D virus, contains multiple mutations in CA: H87R, A88G, P90D, P93A, and Q112D. To investigate how an IFN-hypersensitive virus can evolve to overcome IFN-β-mediated blocks targeting the viral capsid, we adapted the RGDA/Q112D virus in IFN-β-treated cells. We successfully isolated IFN-β-resistant viruses which contained either a single Q4R substitution or the double amino acid change G94D/G116R. These two IFN-β resistance mutations variably changed the sensitivity of CA binding to human myxovirus resistance B (MxB), cleavage and polyadenylation specificity factor 6 (CPSF6), and cyclophilin A (CypA), indicating that the observed loss of sensitivity was not due to interactions with these known host CA-interacting factors. In contrast, the two mutations apparently functioned through distinct mechanisms. The Q4R mutation dramatically accelerated the kinetics of reverse transcription and initiation of uncoating of the RGDA/Q112D virus in the presence or absence of IFN-β, whereas the G94D/G116R mutations affected reverse transcription only in the presence of IFN-β, most consistent with a mechanism of the disruption of binding to an unknown IFN-β-regulated host factor. These results suggest that HIV-1 can exploit multiple, known host factor-independent pathways to avoid IFN-β-mediated restriction by altering capsid sequences and subsequent biological properties. HIV-1 infection causes robust innate immune activation in virus-infected patients. This immune activation is characterized by elevated levels of type I interferons (IFNs), which can block HIV-1 replication. Recent studies suggest that the viral capsid protein (CA) is a determinant for the sensitivity of HIV-1 to IFN-mediated restriction. Specifically, it was reported that the loss of CA interactions with CPSF6 or CypA leads to higher IFN sensitivity. However, the molecular mechanism of CA adaptation to IFN sensitivity is largely unknown. Here, we experimentally evolved an IFN-β-hypersensitive CA mutant which showed decreased binding to CPSF6 and CypA in IFN-β-treated cells. The CA mutations that emerged from this adaptation indeed conferred IFN-β resistance. Our genetic assays suggest a limited contribution of known host factors to IFN-β resistance. Strikingly, one of these mutations accelerated the kinetics of reverse transcription and uncoating. Our findings suggest that HIV-1 selected multiple, known host factor-independent pathways to avoid IFN-β-mediated restriction.
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http://dx.doi.org/10.1128/JVI.00986-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6854511PMC
December 2019

Knowledge About Oral PrEP Among Transgender Women in New York City.

AIDS Behav 2019 Oct;23(10):2779-2783

Northwestern University Feinberg School of Medicine, and Biomedical Engineering in the McCormick School of Engineering and Applied Sciences, Chicago, IL, USA.

This paper grows our understanding about PrEP knowledge in transgender women (TW) to improve PrEP-focused education/outreach. Research took place in New York City. We conducted four focus groups in English or Spanish (N = 18). Discussions focused on participants' perceptions and knowledge of oral PrEP. Most participants knew that PrEP is efficacious and requires consistent use. However, some participants were skeptical of medications; others acknowledged that false assumptions about PrEP exist among TW. Most TW in our focus groups were informed about PrEP through clinics or community-based organizations. Some participants felt that messages about medications were oversimplified, and wanted more information.
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http://dx.doi.org/10.1007/s10461-019-02584-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6790168PMC
October 2019

Cervical and systemic concentrations of long acting hormonal contraceptive (LARC) progestins depend on delivery method: Implications for the study of HIV transmission.

PLoS One 2019 16;14(5):e0214152. Epub 2019 May 16.

Department of Obstetrics, Gynecology, and Women's Health, University of Missouri, Columbia, MO, United States of America.

Progestin-only long-acting reversible contraceptives (LARCs) are increasingly popular among women seeking contraception; however, recent epidemiological studies suggest that systemically administered medroxyprogesterone acetate (MPA) may increase HIV acquisition. In order to determine the exact mechanisms underlying increases in transmission specific to MPA use and to test safer, alternative contraceptive progestin types and delivery methods, in vitro modeling studies must be performed. To achieve this, it is imperative that accurate hormone concentrations be utilized when modeling progestin-mediated outcomes, as the down-stream effects are dose-dependent. The local concentrations of progestins to which the lower female genital tract tissues are exposed after initiation of LARCs are unknown, but they likely differ from peripheral concentrations, dependent upon the progestin type and delivery method. Here, we measured in vivo endocervical and plasma concentrations of (1) systemically-delivered depo MPA (DMPA), (2) levonorgestrel (LNG) delivered via intrauterine system (IUS) and (3) etonogestrel (ETG) delivered via vaginal ring in women who recently initiated contraception treatment. Levels of ETG and LNG in cervical secretions were 100-200 fold higher than plasma levels. In contrast, measurable MPA levels were approximately 10-fold higher in plasma compared to cervical secretions. These results will inform the design of accurate in vitro studies on the influence of progestins on epithelial cells, tissue explants, and peripheral blood cells, to be able to better predict in vivo outcomes. Subsequent observations will aid in determining how MPA might influence HIV acquisition and may facilitate identification of optimal progestin-containing LARC alternatives for women at high risk for HIV infection.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0214152PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6522049PMC
January 2020

Increased mucosal neutrophil survival is associated with altered microbiota in HIV infection.

PLoS Pathog 2019 04 11;15(4):e1007672. Epub 2019 Apr 11.

Department of Pharmaceutics, University of Washington, Seattle, WA, United States of America.

Gastrointestinal (GI) mucosal dysfunction predicts and likely contributes to non-infectious comorbidities and mortality in HIV infection and persists despite antiretroviral therapy. However, the mechanisms underlying this dysfunction remain incompletely understood. Neutrophils are important for containment of pathogens but can also contribute to tissue damage due to their release of reactive oxygen species and other potentially harmful effector molecules. Here we used a flow cytometry approach to investigate increased neutrophil lifespan as a mechanism for GI neutrophil accumulation in chronic, treated HIV infection and a potential role for gastrointestinal dysbiosis. We report that increased neutrophil survival contributes to neutrophil accumulation in colorectal biopsy tissue, thus implicating neutrophil lifespan as a new therapeutic target for mucosal inflammation in HIV infection. Additionally, we characterized the intestinal microbiome of colorectal biopsies using 16S rRNA sequencing. We found that a reduced Lactobacillus: Prevotella ratio associated with neutrophil survival, suggesting that intestinal bacteria may contribute to GI neutrophil accumulation in treated HIV infection. Finally, we provide evidence that Lactobacillus species uniquely decrease neutrophil survival and neutrophil frequency in vitro, which could have important therapeutic implications for reducing neutrophil-driven inflammation in HIV and other chronic inflammatory conditions.
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http://dx.doi.org/10.1371/journal.ppat.1007672DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6459500PMC
April 2019

Defining characteristics of genital health in South African adolescent girls and young women at high risk for HIV infection.

PLoS One 2019 4;14(4):e0213975. Epub 2019 Apr 4.

Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa.

The genital tract of African women has been shown to differ from what is currently accepted as 'normal', defined by a pH≤4.5 and lactobacilli-dominated microbiota. Adolescent girls and young women (AGYW) from sub-Saharan Africa are at high risk for HIV, and we hypothesized that specific biological factors are likely to be influential. This study aimed to compare characteristics of vaginal health in HIV-negative AGYW (16-22-years-old), from two South African communities, to international norms. We measured plasma hormones, vaginal pH, presence of BV (Nugent scoring), sexually transmitted infections (multiplex PCR for Chlamydia trachomatis, Neisseria gonorrhoea, Trichomonas vaginalis, Mycoplasma genitalium) and candidiasis (Gram stain) in AGYW (n = 298) from Cape Town and Soweto. Cervicovaginal microbiota was determined by 16S pyrosequencing; 44 genital cytokines were measured by Luminex; and cervical T-cell activation/proliferation (CCR5, HLA-DR, CD38, Ki67) was measured by multiparametric flow cytometry. 90/298 (30.2%) AGYW were negative for BV, candidiasis and bacterial STIs. L. crispatus and L. iners were the dominant bacteria in cervicovaginal swabs, and the median vaginal pH was 4.7. AGYW with L. crispatus-dominant microbiota (42.4%) generally had the lowest cytokine concentrations compared to women with more diverse microbiota (34/44 significantly upregulated cytokines). Frequencies of CCR5+CD4+ T-cells co-expressing CD38 and HLA-DR correlated positively with interleukin (IL)-6, TNF-α, GRO-α, macrophage inflammatory protein (MIP)-1α, and IL-9. While endogenous oestrogen had an immune-dampening effect on IL-6, TNF-related apoptosis-inducing ligand (TRAIL) and IL-16, injectable hormone contraceptives (DMPA and Net-EN) were associated with significantly lower endogenous hormone concentrations (p<0.0001 for oestrogen and progesterone) and upregulation of 34/44 cytokines. Since genital inflammation and the presence of activated CD4+ T cells in the genital tract have been implicated in increased HIV risk in South African women, the observed high levels of genital cellular activation and cytokines from AGYW may point towards biological factors increasing HIV risk in this region.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0213975PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6448899PMC
December 2019

Bridging Vaccine-Induced HIV-1 Neutralizing and Effector Antibody Responses in Rabbit and Rhesus Macaque Animal Models.

J Virol 2019 05 1;93(10). Epub 2019 May 1.

Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, USA.

Studies in animal models are essential prerequisites for clinical trials of candidate HIV vaccines. Small animals, such as rabbits, are used to evaluate promising strategies prior to further immunogenicity and efficacy testing in nonhuman primates. Our goal was to determine how HIV-specific vaccine-elicited antibody responses, epitope specificity, and Fc-mediated functions in the rabbit model can predict those in the rhesus macaque (RM) model. Detailed comparisons of the HIV-1-specific IgG response were performed on serum from rabbits and RM given identical modified vaccinia virus Ankara-prime/gp120-boost immunization regimens. We found that vaccine-induced neutralizing antibody, gp120-binding antibody levels and immunodominant specificities, antibody-dependent cellular phagocytosis of HIV-1 virions, and antibody-dependent cellular cytotoxicity (ADCC) responses against gp120-coated target cells were similar in rabbits and RM. However, we also identified characteristics of humoral immunity that differed across species. ADCC against HIV-infected target cells was elicited in rabbits but not in RM, and we observed differences among subdominantly targeted epitopes. Human Fc receptor binding assays and analysis of antibody-cell interactions indicated that rabbit vaccine-induced antibodies effectively recruited and activated human natural killer cells, while vaccine-elicited RM antibodies were unable to activate either human or RM NK cells. Thus, our data demonstrate that both Fc-independent and Fc-dependent functions of rabbit antibodies can be measured with commonly used assays; however, the ability of immunogenicity studies performed in rabbits to predict responses in RM will vary depending on the particular immune parameter of interest. Nonneutralizing antibody functions have been associated with reduced infection risk, or control of virus replication, for HIV-1 and related viruses. It is therefore critical to evaluate development of these responses throughout all stages of preclinical testing. Rabbits are conventionally used to evaluate the ability of vaccine candidates to safely elicit antibodies that bind and neutralize HIV-1. However, it remained unexplored how effectively rabbits model the development of nonneutralizing antibody responses in primates. We administered identical HIV-1 vaccine regimens to rabbits and rhesus macaques and performed detailed comparisons of vaccine-induced antibody responses. We demonstrated that nonneutralizing HIV-specific antibody responses can be studied in the rabbit model and have identified aspects of these responses that are common, and those that are unique, to rabbits and rhesus macaques. Our findings will help determine how to best utilize preclinical rabbit and rhesus macaque models to accelerate HIV vaccine candidate testing in human trials.
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http://dx.doi.org/10.1128/JVI.02119-18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6498063PMC
May 2019

Effects of three long-acting reversible contraceptive methods on HIV target cells in the human uterine cervix and peripheral blood.

Reprod Biol Endocrinol 2019 Feb 22;17(1):26. Epub 2019 Feb 22.

Department of Obstetrics, Gynecology and Women's Health, University of Missouri School of Medicine, Columbia, MO, USA.

Background: Hormonal contraceptives, particularly depot medroxyprogesterone acetate (DMPA), have been reported to be associated with substantially enhanced HIV acquisition; however, the biological mechanisms of this risk remain poorly understood. We aimed to investigate the effects of different hormonal contraceptives on the expression of the HIV co-receptors, CXCR4 and CCR5, on female endocervical and peripheral blood T cells.

Methods: A total of 59 HIV-negative women were enrolled, including 15 initiating DMPA, 28 initiating a levonorgestrel-releasing intrauterine device (LNG-IUD) and 16 initiating an etonogestrel (ETG)-delivering vaginal ring. Peripheral blood and endocervical cytobrush specimens were collected at enrollment and 3-4 weeks after contraception initiation to analyze the expression of CXCR4 and CCR5, on CD4 and CD8 T cells using flow cytometry.

Results: Administration of DMPA increased the percentages of CD4 and CD8 T cells expressing CCR5 in the endocervix but not in the peripheral blood. Administration of the LNG-IUD or the ETG vaginal ring did not affect the percentages of T lymphocytes expressing CXCR4 or CCR5 in the female cervix or peripheral blood.

Conclusions: Increase in the percentage of endocervical T cells expressing CCR5 upon DMPA exposure provides a plausible biological explanation for the association between DMPA use and an elevated risk of HIV infection.
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http://dx.doi.org/10.1186/s12958-019-0469-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6387540PMC
February 2019

Rare Detection of Antiviral Functions of Polyclonal IgA Isolated from Plasma and Breast Milk Compartments in Women Chronically Infected with HIV-1.

J Virol 2019 04 21;93(7). Epub 2019 Mar 21.

Duke Human Vaccine Institute, Duke University, Durham, North Carolina, USA

The humoral response to invading mucosal pathogens comprises multiple antibody isotypes derived from systemic and mucosal compartments. To understand the contribution of each antibody isotype/source to the mucosal humoral response, parallel investigation of the specificities and functions of antibodies within and across isotypes and compartments is required. The role of IgA against HIV-1 is complex, with studies supporting a protective role as well as a role for serum IgA in blocking effector functions. Thus, we explored the fine specificity and function of IgA in both plasma and mucosal secretions important to infant HIV-1 infection, i.e., breast milk. IgA and IgG were isolated from milk and plasma from 20 HIV-1-infected lactating Malawian women. HIV-1 binding specificities, neutralization potency, inhibition of virus-epithelial cell binding, and antibody-mediated phagocytosis were measured. Fine-specificity mapping showed IgA and IgG responses to multiple HIV-1 Env epitopes, including conformational V1/V2 and linear V2, V3, and constant region 5 (C5). Env IgA was heterogeneous between the milk and systemic compartments (Env IgA, τ = 0.00 to 0.63, = 0.0046 to 1.00). Furthermore, IgA and IgG appeared compartmentalized as there was a lack of correlation between the specificities of Env-specific IgA and IgG (in milk, τ = -0.07 to 0.26, = 0.35 to 0.83). IgA and IgG also differed in functions: while neutralization and phagocytosis were consistently mediated by milk and plasma IgG, they were rarely detected in IgA from both milk and plasma. Understanding the ontogeny of the divergent IgG and IgA antigen specificity repertoires and their effects on antibody function will inform vaccination approaches targeted toward mucosal pathogens. Antibodies within the mucosa are part of the first line of defense against mucosal pathogens. Evaluating mucosal antibody isotypes, specificities, and antiviral functions in relationship to the systemic antibody profile can provide insights into whether the antibody response is coordinated in response to mucosal pathogens. In a natural immunity cohort of HIV-infected lactating women, we mapped the fine specificity and function of IgA in breast milk and plasma and compared these with the autologous IgG responses. Antigen specificities and functions differed between IgG and IgA, with antiviral functions (neutralization and phagocytosis) predominantly mediated by the IgG fraction in both milk and plasma. Furthermore, the specificity of milk IgA differed from that of systemic IgA. Our data suggest that milk IgA and systemic IgA should be separately examined as potential correlates of risk. Preventive vaccines may need to employ different strategies to elicit functional antiviral immunity by both antibody isotypes in the mucosa.
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http://dx.doi.org/10.1128/JVI.02084-18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6430545PMC
April 2019

Qualitative Consumer Research on Acceptance of Long-Acting Pre-Exposure Prophylaxis Products Among Men Having Sex with Men and Medical Practitioners in the United States.

AIDS Res Hum Retroviruses 2018 10;34(10):849-856

2 Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine , Chicago, Illinois.

Pre-exposure prophylaxis (PrEP) with oral Truvada prevents HIV infection. However, the adherence to pill taking required for efficacy has sparked interest in developing new antiretroviral delivery systems that decrease such demands. Long-acting formulations, such as injections and implants, represent promising options that require less frequent adherence. It is important, however, that development of these new modalities be driven by understanding of the value seen in them by target users to maximize their uptake. To identify the key product features that impact user acceptance, we used a three-phase marketing research approach. In this study, we describe the results of the first-phase, qualitative focus group research performed in Chicago and San Francisco that explored subjective perceptions of oral versus alternative PrEP modalities among men having sex with men (MSM) and medical practitioners caring for MSM. Data revealed that potential value in long-acting PrEP lies more in simplifying the lives of users rather than in making them more confident in their adherence. The results provide an important guidance for designing and promoting these future long-acting products to enhance their contribution to increasing the current limited uptake of PrEP that will better stem the HIV epidemic.
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http://dx.doi.org/10.1089/AID.2018.0214DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6204559PMC
October 2018

Inflammation weakens HIV prevention.

Authors:
Thomas J Hope

Nat Med 2018 04;24(4):384-385

Department of Cell & Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.

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http://dx.doi.org/10.1038/nm.4534DOI Listing
April 2018

HIV-1-Specific IgA Monoclonal Antibodies from an HIV-1 Vaccinee Mediate Galactosylceramide Blocking and Phagocytosis.

J Virol 2018 04 14;92(7). Epub 2018 Mar 14.

Duke Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina, USA

Vaccine-elicited humoral immune responses comprise an array of antibody forms and specificities, with only a fraction contributing to protective host immunity. Elucidation of antibody effector functions responsible for protective immunity against human immunodeficiency virus type 1 (HIV-1) acquisition is a major goal for the HIV-1 vaccine field. Immunoglobulin A (IgA) is an important part of the host defense against pathogens; however, little is known about the role of vaccine-elicited IgA and its capacity to mediate antiviral functions. To identify the antiviral functions of HIV-1-specific IgA elicited by vaccination, we cloned HIV-1 envelope-specific IgA monoclonal antibodies (MAbs) by memory B cell cultures from peripheral blood mononuclear cells from an RV144 vaccinee and produced two IgA clonal cell lines (HG129 and HG130) producing native, nonrecombinant IgA MAbs. The HG129 and HG130 MAbs mediated phagocytosis by monocytes, and HG129 blocked HIV-1 Env glycoprotein binding to galactosylceramide, an alternative HIV-1 receptor. These findings elucidate potential antiviral functions of vaccine-elicited HIV-1 envelope-specific IgA that may act to block HIV-1 acquisition at the portal of entry by preventing HIV-1 binding to galactosylceramide and mediating antibody Fc receptor-mediated virion phagocytosis. Furthermore, these findings highlight the complex and diverse interactions of vaccine-elicited IgA with pathogens that depend on IgA fine specificity and form (e.g., multimeric or monomeric) in the systemic circulation and mucosal compartments. Host-pathogen interactions involve numerous immune mechanisms that can lead to pathogen clearance. Understanding the nature of antiviral immune mechanisms can inform the design of efficacious HIV-1 vaccine strategies. Evidence suggests that both neutralizing and nonneutralizing antibodies can mediate some protection against HIV in animal models. Although numerous studies have characterized the functional properties of HIV-1-specific IgG, more studies are needed on the functional attributes of HIV-1-specific IgA, specifically for vaccine-elicited IgA. Characterization of the functional properties of HIV-1 Env-specific IgA monoclonal antibodies from human vaccine clinical trials are critical toward understanding the capacity of the host immune response to block HIV-1 acquisition.
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http://dx.doi.org/10.1128/JVI.01552-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5972890PMC
April 2018

Converging epidemics of sexually transmitted infections and bacterial vaginosis in southern African female adolescents at risk of HIV.

Int J STD AIDS 2018 05 4;29(6):531-539. Epub 2017 Dec 4.

1 Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa.

Adolescents in Africa are at high risk for HIV infection, other sexually transmitted infections (STIs) and bacterial vaginosis (BV). Since behavior and burden of STIs/BV may influence HIV risk, behavioral risk factors and prevalence of STIs/BV were compared in HIV-seronegative adolescent females (n = 298; 16-22 years) from two South African communities (Soweto and Cape Town). STIs ( Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, Mycoplasma genitalium, herpes simplex virus (HSV)-1, HSV-2, Treponema pallidum, and Haemophilus ducreyi) were detected by multiplex polymerase chain reaction, human papillomavirus (HPV) by Roche Linear Array, and BV by Nugent scoring. Rates of BV (Nugent ≥7; 46.6%) and HPV (66.8%) were high in both communities. Prevalence of C. trachomatis and N. gonorrhoeae were >2-fold higher in Cape Town than Soweto (Chlamydia: 42% [62/149] versus 18% [26/148], p < 0.0001; gonorrhoea 11% [17/149] versus 5% [7/148], p = 0.05). Only 24% of adolescents with vaginal discharge-causing STIs or BV were symptomatic. In South African adolescents, clinical symptoms compatible with vaginal discharge syndrome had a sensitivity of 23% and specificity of 85% for the diagnosis of discharge-causing STI or BV. In a region with high HIV prevalence and incidence, >70% of young women with treatable conditions that could enhance HIV risk would have been missed because they lacked symptoms associated with syndromic management.
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http://dx.doi.org/10.1177/0956462417740487DOI Listing
May 2018

Distinguishing signal from autofluorescence in cryogenic correlated light and electron microscopy of mammalian cells.

J Struct Biol 2018 01 25;201(1):15-25. Epub 2017 Oct 25.

Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute (HHMI), California Institute of Technology, Pasadena, CA 91125, USA. Electronic address:

In cryogenic correlated light and electron microscopy (cryo-CLEM), frozen targets of interest are identified and located on EM grids by fluorescence microscopy and then imaged at higher resolution by cryo-EM. Whilst working with these methods, we discovered that a variety of mammalian cells exhibit strong punctate autofluorescence when imaged under cryogenic conditions (80 K). Autofluorescence originated from multilamellar bodies (MLBs) and secretory granules. Here we describe a method to distinguish fluorescent protein tags from these autofluorescent sources based on the narrower emission spectrum of the former. The method is first tested on mitochondria and then applied to examine the ultrastructural variability of secretory granules within insulin-secreting pancreatic beta-cell-derived INS-1E cells.
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http://dx.doi.org/10.1016/j.jsb.2017.10.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5771259PMC
January 2018

Early cytoplasmic uncoating is associated with infectivity of HIV-1.

Proc Natl Acad Sci U S A 2017 08 7;114(34):E7169-E7178. Epub 2017 Aug 7.

Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611

After fusion, HIV delivers its conical capsid into the cytoplasm. To release the contained reverse-transcribing viral genome, the capsid must disassemble in a process termed uncoating. Defining the kinetics, dynamics, and cellular location of uncoating of virions leading to infection has been confounded by defective, noninfectious particles and the stochastic minefield blocking access to host DNA. We used live-cell fluorescent imaging of intravirion fluid phase markers to monitor HIV-1 uncoating at the individual particle level. We find that HIV-1 uncoating of particles leading to infection is a cytoplasmic process that occurs ∼30 min postfusion. Most, but not all, of the capsid protein is rapidly shed in tissue culture and primary target cells, independent of entry pathway. Extended time-lapse imaging with less than one virion per cell allows identification of infected cells by Gag-GFP expression and directly links individual particle behavior to infectivity, providing unprecedented insights into the biology of HIV infection.
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http://dx.doi.org/10.1073/pnas.1706245114DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5576815PMC
August 2017

Long-term direct visualization of passively transferred fluorophore-conjugated antibodies.

J Immunol Methods 2017 11 2;450:66-72. Epub 2017 Aug 2.

Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA; Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA; Department of Obstetrics and Gynecology, Northwestern University, Chicago, IL, USA. Electronic address:

The use of therapeutic antibodies, delivered by intravenous (IV) instillation, is a rapidly expanding area of biomedical treatment for a variety of conditions. However, little is known about how the antibodies are anatomically distributed following infusion and the underlying mechanism mediating therapeutic antibody distribution to specific anatomical sites remains to be elucidated. Current efforts utilize low resolution and sensitivity methods such as ELISA and indirect labeling imaging techniques, which often leads to high background and difficulty in assessing biodistribution. Here, using the in vivo non-human primate model, we demonstrate that it is possible to utilize the fluorophores Cy5 and Cy3 directly conjugated to antibodies for direct visualization and quantification of passively transferred antibodies in plasma, tissue, and in mucosal secretions. Antibodies were formulated with 1-2 fluorophores per antibody to minimally influence antibody function. Fluorophore conjugated Gamunex-C (pooled human IgG) were tested for binding to protein A, via surface plasmon resonance, and showed similar levels of binding when compared to unlabeled Gamunex-C. In order to assess the effect fluorophore labeling has on turnover and localization, rhesus macaques were IV infused with either labeled or unlabeled Gamunex-C. Plasma, vaginal Weck-Cel fluid, cervicovaginal mucus, and vaginal/rectal tissue biopsies were collected up to 8weeks. Similar turnover and biodistribution was observed between labeled and unlabeled antibodies, showing that the labeling process did not have an obvious deleterious effect on localization or turnover. Cy5 and Cy3 labeled antibodies were readily detected in the same pattern regardless of fluorophore. Tissue distribution was measured in macaque vaginal and rectal biopsies. The labeled antibody in macaque biopsies was found to have similar biodistribution pattern to endogenous antibodies in macaque and human tissues. In the vaginal and rectal mucosa, endogenous and infused antibodies were found primarily within the lamina propria. In the mucosal squamous epithelium of the vaginal vault, significant antibody was also observed in a striated pattern in the superficial, nonviable, stratum corneum. Endogenous antibody distribution in both human and macaque squamous tissues exhibited a similar pattern as seen with the labeled and unlabeled antibodies. This proof-of-principle study reveals that the labeled antibody is stable and physiologically similar relative to endogenous antibody setting the stage for future work to better understand the mechanisms of how antibodies reach unique anatomical sites. Direct visualization of fluorophore-conjugated antibodies following passive infusion can be utilized to assess the kinetics of biodistribution of infused antibodies and may be a useful approach to monitor and predict efficacy of therapeutic antibodies.
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http://dx.doi.org/10.1016/j.jim.2017.07.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5603196PMC
November 2017

HIV-1 selectively targets gut-homing CCR6+CD4+ T cells via mTOR-dependent mechanisms.

JCI Insight 2017 Aug 3;2(15). Epub 2017 Aug 3.

Centre de recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Québec, Canada.

Gut-associated lymphoid tissues are enriched in CCR6+ Th17-polarized CD4+ T cells that contribute to HIV-1 persistence during antiretroviral therapy (ART). This raises the need for Th17-targeted immunotherapies. In an effort to identify mechanisms governing HIV-1 permissiveness/persistence in gut-homing Th17 cells, we analyzed the transcriptome of CCR6+ versus CCR6- T cells exposed to the gut-homing inducer retinoic acid (RA) and performed functional validations in colon biopsies of HIV-infected individuals receiving ART (HIV+ART). Although both CCR6+ and CCR6- T cells acquired gut-homing markers upon RA exposure, the modulation of unique sets of genes coincided with preferential HIV-1 replication in RA-treated CCR6+ T cells. This molecular signature included the upregulation of HIV-dependency factors acting at entry/postentry levels, such as the CCR5 and PI3K/Akt/mTORC1 signaling pathways. Of note, mTOR expression/phosphorylation was distinctively induced by RA in CCR6+ T cells. Consistently, mTOR inhibitors counteracted the effect of RA on HIV replication in vitro and viral reactivation in CD4+ T cells from HIV+ART individuals via postentry mechanisms independent of CCR5. Finally, CCR6+ versus CCR6- T cells infiltrating the colons of HIV+ART individuals expressed unique molecular signatures, including higher levels of CCR5, integrin β7, and mTOR phosphorylation. Together, our results identify mTOR as a druggable key regulator of HIV permissiveness in gut-homing CCR6+ T cells.
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http://dx.doi.org/10.1172/jci.insight.93230DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5543920PMC
August 2017