Publications by authors named "Lisa Poppe"

8 Publications

  • Page 1 of 1

Presence of antibody-dependent cellular cytotoxicity (ADCC) against SARS-CoV-2 in COVID-19 plasma.

PLoS One 2021 4;16(3):e0247640. Epub 2021 Mar 4.

Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE, United States of America.

Background: Neutralizing-antibody (nAb) is the major focus of most ongoing COVID-19 vaccine trials. However, nAb response against SARS-CoV-2, when present, decays rapidly. Given the myriad roles of antibodies in immune responses, it is possible that antibodies could also mediate protection against SARS-CoV-2 via effector mechanisms such as antibody-dependent cellular cytotoxicity (ADCC), which we sought to explore here.

Methods: Plasma of 3 uninfected controls and 20 subjects exposed to, or recovering from, SARS-CoV-2 infection were collected from U.S. and sub-Saharan Africa. Immunofluorescence assay was used to detect the presence of SARS-CoV-2 specific IgG antibodies in the plasma samples. SARS-CoV-2 specific neutralizing capability of these plasmas was assessed with SARS-CoV-2 spike pseudotyped virus. ADCC activity was assessed with a calcein release assay.

Results: SARS-CoV-2 specific IgG antibodies were detected in all COVID-19 subjects studied. All but three COVID-19 subjects contained nAb at high potency (>80% neutralization). Plasma from 19/20 of COVID-19 subjects also demonstrated strong ADCC activity against SARS-CoV-2 spike glycoprotein, including two individuals without nAb against SARS-CoV-2.

Conclusion: Both neutralizing and non-neutralizing COVID-19 plasmas can mediate ADCC. Our findings argue that evaluation of potential vaccines against SARS-CoV-2 should include investigation of the magnitude and durability of ADCC, in addition to nAb.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0247640PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7932539PMC
March 2021

Characterization of recombinant gorilla adenovirus HPV therapeutic vaccine PRGN-2009.

JCI Insight 2021 Apr 8;6(7). Epub 2021 Apr 8.

Laboratory of Tumor Immunology and Biology, Center for Cancer Research, National Cancer Institute (NCI), NIH, Bethesda, Maryland, USA.

There are approximately 44,000 cases of human papillomavirus-associated (HPV-associated) cancer each year in the United States, most commonly caused by HPV types 16 and 18. Prophylactic vaccines successfully prevent healthy people from acquiring HPV infections via HPV-specific antibodies. In order to treat established HPV-associated malignancies, however, new therapies are necessary. Multiple recombinant gorilla adenovirus HPV vaccine constructs were evaluated in NSG-β2m-/- peripheral blood mononuclear cell-humanized mice bearing SiHa, a human HPV16+ cervical tumor, and/or in the syngeneic HPV16+ TC-1 model. PRGN-2009 is a therapeutic gorilla adenovirus HPV vaccine containing multiple cytotoxic T cell epitopes of the viral oncoproteins HPV 16/18 E6 and E7, including T cell enhancer agonist epitopes. PRGN-2009 treatment reduced tumor volume and increased CD8+ and CD4+ T cells in the tumor microenvironment of humanized mice bearing the human cervical tumor SiHa. PRGN-2009 monotherapy in the syngeneic TC-1 model also reduced tumor volumes and weights, generated high levels of HPV16 E6-specific T cells, and increased multifunctional CD8+ and CD4+ T cells in the tumor microenvironment. These studies provide the first evaluation to our knowledge of a therapeutic gorilla adenovirus HPV vaccine, PRGN-2009, showing promising preclinical antitumor efficacy and induction of HPV-specific T cells, along with the rationale for its evaluation in clinical trials.
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http://dx.doi.org/10.1172/jci.insight.141912DOI Listing
April 2021

The Pediatric Obesity Microbiome and Metabolism Study (POMMS): Methods, Baseline Data, and Early Insights.

Obesity (Silver Spring) 2021 Mar;29(3):569-578

Department of Pediatrics, Duke University, Durham, North Carolina, USA.

Objective: The purpose of this study was to establish a biorepository of clinical, metabolomic, and microbiome samples from adolescents with obesity as they undergo lifestyle modification.

Methods: A total of 223 adolescents aged 10 to 18 years with BMI ≥95th percentile were enrolled, along with 71 healthy weight participants. Clinical data, fasting serum, and fecal samples were collected at repeated intervals over 6 months. Herein, the study design, data collection methods, and interim analysis-including targeted serum metabolite measurements and fecal 16S ribosomal RNA gene amplicon sequencing among adolescents with obesity (n = 27) and healthy weight controls (n = 27)-are presented.

Results: Adolescents with obesity have higher serum alanine aminotransferase, C-reactive protein, and glycated hemoglobin, and they have lower high-density lipoprotein cholesterol when compared with healthy weight controls. Metabolomics revealed differences in branched-chain amino acid-related metabolites. Also observed was a differential abundance of specific microbial taxa and lower species diversity among adolescents with obesity when compared with the healthy weight group.

Conclusions: The Pediatric Metabolism and Microbiome Study (POMMS) biorepository is available as a shared resource. Early findings suggest evidence of a metabolic signature of obesity unique to adolescents, along with confirmation of previously reported findings that describe metabolic and microbiome markers of obesity.
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http://dx.doi.org/10.1002/oby.23081DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7927749PMC
March 2021

The Presence of Antibody-Dependent Cell Cytotoxicity-Mediating Antibodies in Kaposi Sarcoma-Associated Herpesvirus-Seropositive Individuals Does Not Correlate with Disease Pathogenesis or Progression.

J Immunol 2020 11 30;205(10):2742-2749. Epub 2020 Sep 30.

Nebraska Center for Virology, Lincoln, NE 68583;

Although the immune response is likely to play a pivotal role in controlling Kaposi sarcoma (KS)-associated herpesvirus (KSHV) and preventing disease development, the exact factors responsible for that control remain ill defined. T cell responses are weak and variable, and neutralizing Abs are more frequently detected in individuals with KS. This suggests a potential role for nonneutralizing Abs, which to date have been largely uninvestigated. Ab-dependent cell cytotoxicity (ADCC) is a common effector function for nonneutralizing Abs and is known to play a protective role in other herpesvirus infections; yet, ADCC has never been investigated in the context of KSHV infection. In this study, we provide, to our knowledge, the first evidence that anti-KSHV Abs are capable of mediating ADCC responses against infected human cells undergoing lytic reactivation. ADCC activity significantly higher than seronegative controls was detected in 24 of 68 KSHV-seropositive individuals tested. However, ADCC responses were not associated with KS development or progression. ADCC activity was also found to be independent of HIV status, sex, age, KSHV Ab titer, and KSHV-neutralizing activity. Nevertheless, additional investigations into effector cell function between KS and asymptomatic individuals are needed to determine whether ADCC has a role in preventing KS.
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http://dx.doi.org/10.4049/jimmunol.2000489DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7751798PMC
November 2020

High nonnucleoside reverse transcriptase inhibitor resistance levels in HIV-1-infected Zambian mother-infant pairs.

AIDS 2020 10;34(12):1833-1842

Nebraska Center for Virology.

Objective(s): To elucidate relationships in antiretroviral resistance between HIV-1-infected mother-infant pairs by defining the resistance profiles in the mothers and infants and quantifying drug resistance prevalence in the pairs post-Option B+ implementation.

Design: Collection of dried blood spots from mother-infant pairs during routine HIV-1 screens in Lusaka, Zambia from 2015 to 2018.

Methods: DNA was extracted from the dried blood spots, the HIV-1 pol region was amplified, and the purified proviral DNA was sequenced using Sanger sequencing. Drug resistance mutations (DRM) were identified in sequenced DNA using the Stanford HIVdb (https://hivdb.stanford.edu/).

Results: DRM were detected in 45% (44/97) of samples, and these samples were found to harbor resistance to at least two antiretrovirals. The prevalence of nonnucleoside reverse transcriptase inhibitor resistance was significantly higher than that of other antiretroviral classes. DRM were detected disproportionately in infants (67%; 33/49) compared with mothers (23%; 11/48), but the magnitude of resistance did not differ when resistance was detected. The disparity in drug resistance profiles was reinforced in pairwise comparison of resistance profiles in mother-infant pairs.

Conclusion: While Option B+ is effective in reducing mother-to-child transmission, in cases where this regimen fails, high-level nonnucleoside reverse transcriptase inhibitor resistance is frequently detected in infants. This underscores the importance of pretreatment drug resistance screening in both mothers and infants and emphasizes the necessary change to protease inhibitor-based and integrase inhibitor-based regimens for treatment of HIV-1-infected infants and mothers.
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http://dx.doi.org/10.1097/QAD.0000000000002614DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7856309PMC
October 2020

Relationships Between Maternal Antibody Responses and Early Childhood Infection With Kaposi Sarcoma-Associated Herpesvirus.

J Infect Dis 2020 10;222(10):1723-1730

Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, Nebraska, USA.

While mother-to-child transmission is believed to play in important role in early childhood infection with Kaposi sarcoma-associated herpesvirus (KSHV), the maternal immune response remains largely uncharacterized. This study aimed to characterize the longitudinal humoral response to KSHV in a cohort of HIV-infected Zambian mothers without KS and identify potential factors that may influence transmission. In total, 86/124 (69.4%) mothers were found to be KSHV seropositive. Longitudinal KSHV titers were fairly stable over time, although seroreversion was still common. Of the total 124 mothers, 81 had at least 1 child KSHV seroconvert during the 2 years analyzed, while the remaining 43 mothers had KSHV-seronegative children. Mothers of KSHV-negative children had higher geometric mean titers than mothers of KSHV-positive children; however, there was no difference in the presence of neutralizing antibodies. This suggests that a strong anti-KSHV immune response, and potentially nonneutralizing antibodies, may reduce transmission.
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http://dx.doi.org/10.1093/infdis/jiaa288DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7982718PMC
October 2020

HIV drug resistance in infants increases with changing prevention of mother-to-child transmission regimens.

AIDS 2017 08;31(13):1885-1889

aNebraska Center for Virology and School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA bUniversity Teaching Hospital-Lusaka Children's Hospital cUniversity of Zambia School of Medicine, Lusaka, Zambia.

Objectives: The objectives of this study were to determine HIV drug resistance (HIVDR) prevalence in Zambian infants upon diagnosis, and to determine how changing prevention of mother-to-child transmission (PMTCT) drug regimens affect drug resistance.

Design: Dried blood spot (DBS) samples from infants in the Lusaka District of Zambia, obtained during routine diagnostic screening, were collected during four different years representing three different PMTCT drug treatment regimens.

Methods: DNA extracted from dried blood spot samples was used to sequence a 1493 bp region of the reverse transcriptase gene. Sequences were analyzed via the Stanford HIVDRdatabase (http://hivdb.standford.edu) to screen for resistance mutations.

Results: HIVDR in infants increased from 21.5 in 2007/2009 to 40.2% in 2014. Nonnucleoside reverse transcriptase inhibitor resistance increased steadily over the sampling period, whereas nucleoside reverse transcriptase inhibitor resistance and dual class resistance both increased more than threefold in 2014. Analysis of drug resistance scores in each group revealed increasing strength of resistance over time. In 2014, children with reported PMTCT exposure, defined as infant prophylaxis and/or maternal treatment, showed a higher prevalence and strength of resistance compared to those with no reported exposure.

Conclusion: HIVDR is on the rise in Zambia and presents a serious problem for the successful lifelong treatment of HIV-infected children. PMTCT affects both the prevalence and strength of resistance and further research is needed to determine how to mitigate its role leading to resistance.
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http://dx.doi.org/10.1097/QAD.0000000000001569DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5567858PMC
August 2017

Longitudinal analysis of the humoral response to Kaposi's sarcoma-associated herpesvirus after primary infection in children.

J Med Virol 2016 11 11;88(11):1973-81. Epub 2016 May 11.

Nebraska Center for Virology and School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska.

Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent for Kaposi's sarcoma (KS)-one of the most common pediatric cancers in sub-Saharan Africa-however, the factors that lead to disease progression are not fully understood. HIV infection, immunosuppression, and high KSHV viral load increase the risk of developing KS, suggesting that the loss of an effective anti-KSHV immune response may be an important risk factor. However, very little is known about the KSHV-specific immune response prior to KS and less is known about the anti-KSHV immune response during the very early stages of infection. We therefore prospectively followed a cohort of 86 Zambian children for 2 years after primary KSHV seroconversion to characterize the humoral immune response during the early stages of KSHV infection. Plasma, peripheral blood mononuclear cells, and oral swabs were collected from patients every 3 months and analyzed for KSHV-specific antibodies and presence of viral DNA. We observed an approximately 40% KSHV seropositive rate among infected children at time points after primary seroconversion, indicating that seroreversion is common after primary KSHV infection. At the time of primary KSHV seroconversion HIV-infected ART-naïve children had a more robust KSHV antibody response compared to HIV-infected children taking ART and HIV-uninfected children. Conversely, the longitudinal anti-KSHV antibody response was highly variable and did not correlate with available clinical information, HIV/ART status, or presence of KSHV DNA. Collectively, our data suggest that there is limited impact by the variations in the humoral immune response in young children after infection. J. Med. Virol. 88:1973-1981, 2016. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/jmv.24546DOI Listing
November 2016