Publications by authors named "Lourdes Adamson"

16 Publications

  • Page 1 of 1

Cytomegalovirus mediates expansion of IL-15-responsive innate-memory cells with SIV killing function.

J Clin Invest 2021 Jun 21. Epub 2021 Jun 21.

Division of Experimental Medicine, Department of Medicine, UCSF, San Francisco, United States of America.

Inter-individual immune variability is driven predominantly by environmental factors including exposure to chronic infectious agents such as cytomegalovirus (CMV). We investigated the effects of rhesus CMV (RhCMV) on composition and function of the immune system in young macaques. Within months of infection, RhCMV was associated with impressive changes in antigen presenting cells, T cells, and NK cells - and marked expansion of innate-memory CD8+ T cells. These cells express high levels of NKG2A/C and the IL-2- and IL-15-receptor beta chain, CD122. IL-15 was sufficient to drive differentiation of the cells in vitro and in vivo. Expanded NKG2A/C+CD122+CD8+ T cells in RhCMV-infected macaques, but not their NKG2-negative counterparts, were endowed with cytotoxicity against class I-deficient K562 targets and prompt IFN-ɣ production in response to stimulation with IL-12 and IL-18. Because RhCMV clone 68-1 forms the viral backbone of RhCMV-vectored SIV vaccines, we also investigated immune changes following administration of RhCMV 68-1-vectored SIV vaccines. These vaccines led to impressive expansion of NKG2A/C+CD8+ T cells with capacity to inhibit SIV replication ex vivo. Thus, CMV infection and CMV-vectored vaccination drive expansion of functional innate-like CD8 cells via host IL-15 production, suggesting that innate-memory expansion could be achieved by other vaccine platforms expressing IL-15.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1172/JCI148542DOI Listing
June 2021

Quantitative Imaging Analysis of the Spatial Relationship between Antiretrovirals, Reverse Transcriptase Simian-Human Immunodeficiency Virus RNA, and Collagen in the Mesenteric Lymph Nodes of Nonhuman Primates.

Antimicrob Agents Chemother 2021 05 18;65(6). Epub 2021 May 18.

Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA

Human immunodeficiency virus (HIV) persistence in tissue reservoirs is a major barrier to HIV cure. While antiretrovirals (ARVs) suppress viral replication, antiretroviral therapy (ART) interruption results in rapid rebound viremia that may originate from lymphoid tissues. To understand the relationship between anatomic distribution of ARV exposure and viral expression in lymph nodes, we performed mass spectrometry imaging (MSI) of 6 ARVs, RNAscope hybridization for viral RNA (vRNA), and immunohistochemistry of collagen in mesenteric lymph nodes from 8 uninfected and 10 reverse transcriptase simian/human immunodeficiency virus (RT-SHIV)-infected rhesus macaques dosed to steady state with combination ART. MATLAB-based quantitative imaging analysis was used to evaluate spatial and pharmacological relationships between these ARVs, viral RNA (both vRNA cells and follicular dendritic cell [FDC]-bound virions), and collagen deposition. Using MSI, 31% of mesenteric lymph node tissue area was found to be not covered by any ARV. Additionally, 28% of FDC-trapped virions and 21% of infected cells were not exposed to any detected ARV. Of the 69% of tissue area that was covered by cumulative ART exposure, nearly 100% of concentrations were greater than 50% inhibitory concentration (IC) values; however, 52% of total tissue coverage was from only one ARV, primarily maraviroc. Collagen covered ∼35% of tissue area but did not influence ARV distribution heterogeneity. Our findings are consistent with our hypothesis that ARV distribution, in addition to total-tissue drug concentration, must be considered when evaluating viral persistence in lymph nodes and other reservoir tissues.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/AAC.00019-21DOI Listing
May 2021

Antiretroviral Penetration and Drug Transporter Concentrations in the Spleens of Three Preclinical Animal Models and Humans.

Antimicrob Agents Chemother 2020 09 21;64(10). Epub 2020 Sep 21.

University of North Carolina Eshelman School of Pharmacy, Chapel Hill, North Carolina, USA

Adequate antiretroviral (ARV) concentrations in lymphoid tissues are critical for optimal antiretroviral therapy (ART). While the spleen contains 25% of the body's lymphocytes, there are minimal data on ARV penetration in this organ. This study quantified total and protein-unbound splenic ARV concentrations and determined whether drug transporters, sex, or infection status were modifiers of these concentrations in animal models and humans. Two humanized mice models (hu-HSC-Rag [ = 36; 18 HIV-positive (HIV) and 18 HIV-negative (HIV)] and bone marrow-liver-thymus [ = 13; 7 HIV and 6 HIV]) and one nonhuman primate (NHP) model (rhesus macaque [ = 18; 10 SHIV and 8 SHIV]) were dosed to steady state with ARV combinations. HIV human spleens ( = 14) from the National NeuroAIDS Tissue Consortium were analyzed postmortem (up to 24 h postdose). ARV concentrations were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS), drug transporter concentrations were measured with LC-MS proteomics, and protein binding in NHP spleens was determined by rapid equilibrium dialysis. Mice generally had the lowest splenic concentrations of the three species. Protein binding in splenic tissue was 6 to 96%, compared to 76 to 99% in blood plasma. NHPs had quantifiable Mrp4, Bcrp, and Ent1 concentrations, and humans had quantifiable ENT1 concentrations. None significantly correlated with tissue ARV concentrations. There was also no observable influence of infection status or sex. With these dosing strategies, NHP splenic penetration most closely resembled that of humans. These data can inform tissue pharmacokinetic scaling to humans to target HIV reservoirs by identifying important species-related differences.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/AAC.01384-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7508597PMC
September 2020

Antiretroviral Penetration across Three Preclinical Animal Models and Humans in Eight Putative HIV Viral Reservoirs.

Antimicrob Agents Chemother 2019 12 20;64(1). Epub 2019 Dec 20.

University of North Carolina Eshelman School of Pharmacy, Chapel Hill, North Carolina, USA

For HIV cure strategies like "kick and kill" to succeed, antiretroviral (ARV) drugs must reach effective concentrations in putative viral reservoirs. We characterize penetration of six ARVs in three preclinical animal models and humans. We found that standard dosing strategies in preclinical species closely mimicked tissue concentrations in humans for some, but not all, ARVs. These results have implications for interpreting HIV treatment, prevention, or cure interventions between preclinical and clinical models.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/AAC.01639-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7187610PMC
December 2019

Heterogeneous antiretroviral drug distribution and HIV/SHIV detection in the gut of three species.

Sci Transl Med 2019 07;11(499)

Division of Pharmacotherapy and Experimental Therapeutics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.

HIV replication within tissues may increase in response to a reduced exposure to antiretroviral drugs. Traditional approaches to measuring drug concentrations in tissues are unable to characterize a heterogeneous drug distribution. Here, we used mass spectrometry imaging (MSI) to visualize the distribution of six HIV antiretroviral drugs in gut tissue sections from three species (two strains of humanized mice, macaques, and humans). We measured drug concentrations in proximity to CD3 T cells that are targeted by HIV, as well as expression of HIV or SHIV RNA and expression of the MDR1 drug efflux transporter in gut tissue from HIV-infected humanized mice, SHIV-infected macaques, and HIV-infected humans treated with combination antiretroviral drug therapy. Serial 10-μm sections of snap-frozen ileal and rectal tissue were analyzed by MSI for CD3 T cells and MDR1 efflux transporter expression by immunofluorescence and immunohistochemistry, respectively. The tissue slices were analyzed for HIV/SHIV RNA expression by in situ hybridization and for antiretroviral drug concentrations by liquid chromatography-mass spectrometry. The gastrointestinal tissue distribution of the six drugs was heterogeneous. Fifty percent to 60% of CD3 T cells did not colocalize with detectable drug concentrations in the gut tissue. In all three species, up to 90% of HIV/SHIV RNA was found to be expressed in gut tissue with no exposure to drug. These data suggest that there may be gut regions with little to no exposure to antiretroviral drugs, which may result in low-level HIV replication contributing to HIV persistence.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1126/scitranslmed.aap8758DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8273920PMC
July 2019

Antiretroviral Drug Concentrations in Lymph Nodes: A Cross-Species Comparison of the Effect of Drug Transporter Expression, Viral Infection, and Sex in Humanized Mice, Nonhuman Primates, and Humans.

J Pharmacol Exp Ther 2019 09 24;370(3):360-368. Epub 2019 Jun 24.

Eshelman School of Pharmacy (E.B., J.K.F., N.W., A.P.S., C.S., P.C.S., A.D.M.K.) and School of Medicine (M.K., J.V.G., A.D.M.K.), University of North Carolina, Chapel Hill, North Carolina; School of Medicine, Colorado State University, Fort Collins, Colorado (L.R.-M., R.A.); and School of Medicine, University of California, Davis, California (L.A., P.L.)

In a "kick and kill" strategy for human immunodeficiency virus (HIV) eradication, protective concentrations of antiretrovirals (ARVs) in the lymph node are important to prevent vulnerable cells from further HIV infection. However, the factors responsible for drug distribution and concentration into these tissues are largely unknown. Although humanized mice and nonhuman primates (NHPs) are crucial to HIV research, ARV tissue pharmacology has not been well characterized across species. This study investigated the influence of drug transporter expression, viral infection, and sex on ARV penetration within lymph nodes of animal models and humans. Six ARVs were dosed for 10 days in humanized mice and NHPs. Plasma and lymph nodes were collected at necropsy, 24 hours after the last dose. Human lymph node tissue and plasma from deceased patients were collected from tissue banks. ARV, active metabolite, and endogenous nucleotide concentrations were measured by liquid chromatography-tandem mass spectrometry, and drug transporter expression was measured using quantitative polymerase chain reaction and quantitative targeted absolute proteomics. In NHPs and humans, lymph node ARV concentrations were greater than or equal to plasma, and tenofovir diphosphate/deoxyadenosine triphosphate concentration ratios achieved efficacy targets in lymph nodes from all three species. There was no effect of infection or sex on ARV concentrations. Low drug transporter expression existed in lymph nodes from all species, and no predictive relationships were found between transporter gene/protein expression and ARV penetration. Overall, common preclinical models of HIV infection were well suited to predict human ARV exposure in lymph nodes, and low transporter expression suggests primarily passive drug distribution in these tissues. SIGNIFICANCE STATEMENT: During human immunodeficiency virus (HIV) eradication strategies, protective concentrations of antiretrovirals (ARVs) in the lymph node prevent vulnerable cells from further HIV infection. However, ARV tissue pharmacology has not been well characterized across preclinical species used for HIV eradication research, and the influence of drug transporters, HIV infection, and sex on ARV distribution and concentration into the lymph node is largely unknown. Here we show that two animal models of HIV infection (humanized mice and nonhuman primates) were well suited to predict human ARV exposure in lymph nodes. Additionally, we found that drug transporter expression was minimal and-along with viral infection and sex-did not affect ARV penetration into lymph nodes from any species.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1124/jpet.119.259150DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6695867PMC
September 2019

Predicting Efavirenz Concentrations in the Brain Tissue of HIV-Infected Individuals and Exploring their Relationship to Neurocognitive Impairment.

Clin Transl Sci 2019 05 27;12(3):302-311. Epub 2019 Feb 27.

Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.

Sparse data exist on the penetration of antiretrovirals into brain tissue. In this work, we present a framework to use efavirenz (EFV) pharmacokinetic (PK) data in plasma, cerebrospinal fluid (CSF), and brain tissue of eight rhesus macaques to predict brain tissue concentrations in HIV-infected individuals. We then perform exposure-response analysis with the model-predicted EFV area under the concentration-time curve (AUC) and neurocognitive scores collected from a group of 24 HIV-infected participants. Adult rhesus macaques were dosed daily with 200 mg EFV (as part of a four-drug regimen) for 10 days. Plasma was collected at 8 time points over 10 days and at necropsy, whereas CSF and brain tissue were collected at necropsy. In the clinical study, data were obtained from one paired plasma and CSF sample of participants prescribed EFV, and neuropsychological test evaluations were administered across 15 domains. PK modeling was performed using ADAPT version 5.0 Biomedical Simulation Resource, Los Angeles, CA) with the iterative two-stage estimation method. An eight-compartment model best described EFV distribution across the plasma, CSF, and brain tissue of rhesus macaques and humans. Model-predicted median brain tissue concentrations in humans were 31 and 8,000 ng/mL, respectively. Model-predicted brain tissue AUC was highly correlated with plasma AUC (γ = 0.99, P < 0.001) but not CSF AUC (γ = 0.34, P = 0.1) and did not show any relationship with neurocognitive scores (γ < 0.05, P > 0.05). This analysis provides an approach to estimate PK the brain tissue in order to perform PK/pharmacodynamic analyses at the target site.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/cts.12620DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6510381PMC
May 2019

Antiretroviral concentrations and surrogate measures of efficacy in the brain tissue and CSF of preclinical species.

Xenobiotica 2019 Oct 17;49(10):1192-1201. Epub 2018 Dec 17.

a Eshelman School of Pharmacy , University of North Carolina at Chapel Hill , Chapel Hill , NC , USA.

1. Antiretroviral concentrations in cerebrospinal fluid (CSF) are used as surrogate for brain tissue, although sparse data support this. We quantified antiretrovirals in brain tissue across preclinical models, compared them to CSF, and calculated 90% inhibitory quotients (IQ) for nonhuman primate (NHP) brain tissue. Spatial distribution of efavirenz was performed by mass-spectrometry imaging (MSI). 2. HIV or RT-SHIV-infected and uninfected animals from two humanized mouse models (hemopoietic-stem cell/RAG2-,  = 36; bone marrow-liver-thymus/BLT,  =13) and an NHP model (rhesus macaque,  =18) were dosed with six antiretrovirals. Brain tissue, CSF (NHPs), and plasma were collected at necropsy. Drug concentrations were measured by LC-MS/MS. Rapid equilibrium dialysis determined protein binding in NHP brain. 3. Brain tissue penetration of most antiretrovirals were >10-fold lower ( < 0.02) in humanized mice than NHPs. NHP CSF concentrations were >13-fold lower ( <0.02) than brain tissue with poor agreement except for efavirenz ( = 0.91,  = 0.001). Despite 97% brain tissue protein binding, efavirenz achieved IQ>1 in all animals and 2-fold greater white versus gray matter concentration. 4. Brain tissue penetration varied across animal models for all antiretrovirals except raltegravir, and extrapolating brain tissue concentrations between models should be avoided. With the exception of efavirenz, CSF is not a surrogate for brain tissue concentrations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/00498254.2018.1539278DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6579712PMC
October 2019

Multimodal analysis of drug transporter expression in gastrointestinal tissue.

AIDS 2017 07;31(12):1669-1678

aEshelman School of Pharmacy bSchool of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina cSchool of Medicine, Colorado State University, Fort Collins, Colorado dSchool of Medicine, University of California, Davis, California, USA.

Objectives: Drug transporters affect antiretroviral therapy (ART) tissue disposition, but quantitative measures of drug transporter protein expression across preclinical species are not available. Our objective was to use proteomics to obtain absolute transporter concentrations and assess agreement with corresponding gene and immunometric protein data.

Design: In order to make interspecies comparisons, two humanized mouse [hu-HSC-Rag (n = 41); bone marrow-liver-thymus (n = 13)] and one primate [rhesus macaque (nonhuman primate, n = 12)] models were dosed to steady state with combination ART. Ileum and rectum were collected at necropsy and snap frozen for analysis.

Methods: Tissues were analyzed for gene (quantitative PCR) and protein [liquid chromatography-mass spectrometry (LC-MS) proteomics and western blot] expression and localization (immunohistochemistry) of ART efflux and uptake transporters. Drug concentrations were measured by LC-MS/MS. Multivariable regression was used to determine the ability of transporter data to predict tissue ART penetration.

Results: Analytical methods did not agree, with different trends observed for gene and protein expression. For example, quantitative PCR analysis showed a two-fold increase in permeability glycoprotein expression in nonhuman primates versus mice; however, proteomics showed a 200-fold difference in the opposite direction. Proteomics results were supported by immunohistochemistry staining showing extensive efflux transporter localization on the luminal surface of these tissues. ART tissue concentration was variable between species, and multivariable regression showed poor predictive power of transporter data.

Conclusion: Lack of agreement between analytical techniques suggests that resources should be focused on generating downstream measures of protein expression to predict drug exposure. Taken together, these data inform the use of preclinical models for studying ART distribution and the design of targeted therapies for HIV eradication.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/QAD.0000000000001554DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5546623PMC
July 2017

Mass spectrometry imaging reveals heterogeneous efavirenz distribution within putative HIV reservoirs.

Antimicrob Agents Chemother 2015 May 2;59(5):2944-8. Epub 2015 Mar 2.

W. M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, North Carolina, USA

Persistent HIV replication within active viral reservoirs may be caused by inadequate antiretroviral penetration. Here, we used mass spectrometry imaging with infrared matrix-assisted laser desorption-electrospray ionization to quantify the distribution of efavirenz within tissues from a macaque dosed orally to a steady state. Intratissue efavirenz distribution was heterogeneous, with the drug concentrating in the lamina propria of the colon, the primary follicles of lymph nodes, and the brain gray matter. These are the first imaging data of an antiretroviral drug in active viral reservoirs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/AAC.04952-14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4394831PMC
May 2015

Residual viremia in an RT-SHIV rhesus macaque HAART model marked by the presence of a predominant plasma clone and a lack of viral evolution.

PLoS One 2014 5;9(2):e88258. Epub 2014 Feb 5.

Department of Pediatrics, Laboratory of Biochemical Pharmacology, Center for AIDS Research, Emory University School of Medicine, Atlanta, Georgia, United States of America ; Veterans Affairs Medical Center, Decatur, Georgia, United States of America.

Highly active antiretroviral therapy (HAART) significantly reduces HIV-1 replication and prevents progression to AIDS. However, residual low-level viremia (LLV) persists and long-lived viral reservoirs are maintained in anatomical sites. These reservoirs permit a recrudescence of viremia upon cessation of therapy and thus HAART must be maintained indefinitely. HIV-1 reservoirs include latently infected resting memory CD4⁺ T-cells and macrophages which may contribute to residual viremia. It has not been conclusively determined if a component of LLV may also be due to residual replication in cells with sub-therapeutic drug levels and/or long-lived chronically infected cells. In this study, RT-SHIV(mac239) diversity was characterized in five rhesus macaques that received a five-drug HAART regimen [tenofovir, emtricitabine, zidovudine, amdoxovir, (A, C, T, G nucleoside analogs) and the non-nucleoside reverse transcriptase (RT) inhibitor efavirenz]. Before maximal viral load suppression, longitudinal plasma viral RNA RT diversity was analyzed using a 454 sequencer. After suppression, LLV RT diversity (amino acids 65-210) was also assessed. LLV samples had viral levels less than our standard detection limit (50 viral RNA copies/mL) and few transient blips <200 RNA copies/mL. HAART was discontinued in three macaques after 42 weeks of therapy resulting in viral rebound. The level of viral divergence and the prevalence of specific alleles in LLV was similar to pre-suppression viremia. While some LLV sequences contained mutations not observed in the pre-suppression profile, LLV was not characterized by temporal viral evolution or apparent selection of drug resistance mutations. Similarly, resistance mutations were not detected in the viral rebound population. Interestingly, one macaque maintained a putative LLV predominant plasma clone sequence. Together, these results suggest that residual replication did not markedly contribute to LLV and that this model mimics the prevalence and phylogenetic characteristics of LLV during human HAART. Therefore, this model may be ideal for testing HIV-1 eradication strategies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0088258PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3914964PMC
September 2014

Analysis of multiply spliced transcripts in lymphoid tissue reservoirs of rhesus macaques infected with RT-SHIV during HAART.

PLoS One 2014 5;9(2):e87914. Epub 2014 Feb 5.

Center for Comparative Medicine, University of California Davis, Davis, California, United States of America ; Department of Veterinary Molecular Biosciences, University of California Davis, Davis, California, United States of America.

Highly active antiretroviral therapy (HAART) can reduce levels of human immunodeficiency virus type 1 (HIV-1) to undetectable levels in infected individuals, but the virus is not eradicated. The mechanisms of viral persistence during HAART are poorly defined, but some reservoirs have been identified, such as latently infected resting memory CD4⁺ T cells. During latency, in addition to blocks at the initiation and elongation steps of viral transcription, there is a block in the export of viral RNA (vRNA), leading to the accumulation of multiply-spliced transcripts in the nucleus. Two of the genes encoded by the multiply-spliced transcripts are Tat and Rev, which are essential early in the viral replication cycle and might indicate the state of infection in a given population of cells. Here, the levels of multiply-spliced transcripts were compared to the levels of gag-containing RNA in tissue samples from RT-SHIV-infected rhesus macaques treated with HAART. Splice site sequence variation was identified during development of a TaqMan PCR assay. Multiply-spliced transcripts were detected in gastrointestinal and lymphatic tissues, but not the thymus. Levels of multiply-spliced transcripts were lower than levels of gag RNA, and both correlated with plasma virus loads. The ratio of multiply-spliced to gag RNA was greatest in the gastrointestinal samples from macaques with plasma virus loads <50 vRNA copies per mL at necropsy. Levels of gag RNA and multiply-spliced mRNA in tissues from RT-SHIV-infected macaques correlate with plasma virus load.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0087914PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3914874PMC
November 2014

Stereological analysis of bacterial load and lung lesions in nonhuman primates (rhesus macaques) experimentally infected with Mycobacterium tuberculosis.

Am J Physiol Lung Cell Mol Physiol 2011 Nov 26;301(5):L731-8. Epub 2011 Aug 26.

Center for Comparative Medicine, Davis, CA 95616, USA.

Infection with Mycobacterium tuberculosis primarily produces a multifocal distribution of pulmonary granulomas in which the pathogen resides. Accordingly, quantitative assessment of the bacterial load and pathology is a substantial challenge in tuberculosis. Such assessments are critical for studies of the pathogenesis and for the development of vaccines and drugs in animal models of experimental M. tuberculosis infection. Stereology enables unbiased quantitation of three-dimensional objects from two-dimensional sections and thus is suited to quantify histological lesions. We have developed a protocol for stereological analysis of the lung in rhesus macaques inoculated with a pathogenic clinical strain of M. tuberculosis (Erdman strain). These animals exhibit a pattern of infection and tuberculosis similar to that of naturally infected humans. Conditions were optimized for collecting lung samples in a nonbiased, random manner. Bacterial load in these samples was assessed by a standard plating assay, and granulomas were graded and enumerated microscopically. Stereological analysis provided quantitative data that supported a significant correlation between bacterial load and lung granulomas. Thus this stereological approach enables a quantitative, statistically valid analysis of the impact of M. tuberculosis infection in the lung and will serve as an essential tool for objectively comparing the efficacy of drugs and vaccines.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1152/ajplung.00120.2011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3213984PMC
November 2011

Viral decay kinetics in the highly active antiretroviral therapy-treated rhesus macaque model of AIDS.

PLoS One 2010 Jul 23;5(7):e11640. Epub 2010 Jul 23.

Center for Comparative Medicine, University of California Davis, Davis, California, United States of America.

To prevent progression to AIDS, persons infected with human immunodeficiency virus type 1 (HIV-1) must remain on highly active antiretroviral therapy (HAART) indefinitely since this modality does not eradicate the virus. The mechanisms involved in viral persistence during HAART are poorly understood, but an animal model of HAART could help elucidate these mechanisms and enable studies of HIV-1 eradication strategies. Due to the specificity of non-nucleoside reverse transcriptase (RT) inhibitors (NNRTIs) for HIV-1, we have used RT-SHIV, a chimeric virus of simian immunodeficiency virus with RT from HIV-1. This virus is susceptible to NNRTIs and causes an AIDS-like disease in rhesus macaques. In this study, two groups of HAART-treated, RT-SHIV-infected macaques were analyzed to determine viral decay kinetics. In the first group, viral loads were monitored with a standard TaqMan RT-PCR assay with a limit of detection of 50 viral RNA copies per mL. Upon initiation of HAART, viremia decayed in a bi-phasic manner with half-lives of 1.7 and 8.5 days, respectively. A third phase was observed with little further decay. In the second group, the macaques were followed longitudinally with a more sensitive assay utilizing ultracentrifugation to concentrate virus from plasma. Bi-phasic decay of viral RNA was also observed in these animals with half-lives of 1.8 and 5.8 days. Viral loads in these animals during a third phase ranged from 2-58 RNA copies/mL, with little decay over time. The viral decay kinetics observed in these macaques are similar to those reported for HIV-1 infected humans. These results demonstrate that low-level viremia persists in RT-SHIV-infected macaques despite a HAART regimen commonly used in humans.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0011640PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2909142PMC
July 2010

Viral sanctuaries during highly active antiretroviral therapy in a nonhuman primate model for AIDS.

J Virol 2010 Mar 23;84(6):2913-22. Epub 2009 Dec 23.

Center for Comparative Medicine, Department of Veterinary Molecular Biosciences, University of California, Davis, CA 95616, USA.

Highly active antiretroviral therapy (HAART) enables long-term suppression of plasma HIV-1 loads in infected persons, but low-level virus persists and rebounds following cessation of therapy. During HAART, this virus resides in latently infected cells, such as resting CD4(+) T cells, and in other cell types that may support residual virus replication. Therapeutic eradication will require elimination of virus from all reservoirs. We report here a comprehensive analysis of these reservoirs in fluids, cells, and tissues in a rhesus macaque model that mimics HAART in HIV-infected humans. This nonhuman primate model uses RT-SHIV, a chimera of simian immunodeficiency virus containing the HIV-1 reverse transcriptase (RT). Methods were developed for extraction, preamplification, and real-time PCR analyses of viral DNA (vDNA) and viral RNA (vRNA) in tissues from RT-SHIV-infected macaques. These methods were used to identify viral reservoirs in RT-SHIV-infected macaques treated with a potent HAART regimen consisting of efavirenz, emtricitabine, and tenofovir. Plasma virus loads at necropsy ranged from 11 to 28 copies of vRNA per ml. Viral RNA and DNA were detected during HAART, in tissues from numerous anatomical locations. Additional analysis provided evidence for full-length viral RNA in tissues of animals with virus suppressed by HAART. The highest levels of vDNA and vRNA in HAART-treated macaques were in lymphoid tissues, particularly the spleen, lymph nodes, and gastrointestinal tract tissues. This study is the first comprehensive analysis of the tissue and organ distribution of a primate AIDS virus during HAART. These data demonstrate widespread persistence of residual virus in tissues during HAART.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JVI.02356-09DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2826073PMC
March 2010

Induction of simian AIDS in infant rhesus macaques infected with CCR5- or CXCR4-utilizing simian-human immunodeficiency viruses is associated with distinct lesions of the thymus.

J Virol 2004 Feb;78(4):2121-30

Center for Comparative Medicine, University of California, Davis, California 95616, USA.

Newborn rhesus macaques were infected with two chimeric simian-human immunodeficiency virus (SHIV) strains which contain unique human immunodeficiency virus type 1 (HIV-1) env genes and exhibit distinct phenotypes. Infection with either the CCR5-specific SHIV(SF162P3) or the CXCR4-utilizing SHIV(SF33A) resulted in clinical manifestations consistent with simian AIDS. Most prominent in this study was the detection of severe thymic involution in all SHIV(SF33A)-infected infants, which is very similar to HIV-1-induced thymic dysfunction in children who exhibit a rapid pattern of disease progression. In contrast, SHIV(SF162P3) induced only a minor disruption in thymic morphology. Consistent with the distribution of the coreceptors CXCR4 and CCR5 within the thymus, the expression of SHIV(SF162P3) was restricted to the thymic medulla, whereas SHIV(SF33A) was preferentially detected in the cortex. This dichotomy of tissue tropism is similar to the differential tropism of HIV-1 isolates observed in the reconstituted human thymus in SCID-hu mice. Accordingly, our results show that the SHIV-monkey model can be used for the molecular dissection of cell and tissue tropisms controlled by the HIV-1 env gene and for the analysis of mechanisms of viral immunopathogenesis in AIDS. Furthermore, these findings could help explain the rapid progression of disease observed in some HIV-1-infected children.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC369416PMC
http://dx.doi.org/10.1128/jvi.78.4.2121-2130.2004DOI Listing
February 2004