Wagner et al. AIDS Res Ther (2017) 14:7 DOI 10.1186/s12981-017-0135-1
AIDS Research and Therapy Open Access
SHORT REPORT
H1N1 influenza vaccination in HIV‑infected women on effective antiretroviral treatment did not induce measurable antigen‑driven proliferation of the HIV‑1 proviral reservoir Thor A. Wagner1,2*, Hannah C. Huang2, Christen E. Salyer3, Kelly M. Richardson4, Adriana Weinberg4, Sharon Nachman5 and Lisa M. Frenkel1,2 Abstract Objectives: Antigen-induced activation and proliferation of HIV-1-infected cells is hypothesized to be a mechanism of HIV persistence during antiretroviral therapy. The objective of this study was to determine if proliferation of H1N1specific HIV-infected cells could be detected following H1N1 vaccination. Methods: This study utilized cryopreserved PBMC from a previously conducted trial of H1N1 vaccination in HIVinfected pregnant women. HIV-1 DNA concentrations and 437 HIV-1 C2V5 env DNA sequences were analyzed from ten pregnant women on effective antiretroviral therapy, before and 21 days after H1N1 influenza vaccination. Results: HIV-1 DNA concentration did not change after vaccination (median pre- vs. post-vaccination: 95.77 vs. 41.28 copies/million PBMC, p = .37). Analyses of sequences did not detect evidence of HIV replication or proliferation of infected cells. Conclusions: Antigenic stimulation during effective ART did not have a detectable effect on the genetic makeup of the HIV-1 DNA reservoir. Longitudinal comparison of the amount and integration sites of HIV-1 in antigen-specific cells to chronic infections (such as herpesviruses) may be needed to definitively evaluate whether antigenic stimulation induces proliferation of HIV-1 infected cells. Keywords: HIV, HIV DNA, Influenza, Vaccination, H1N1, Pregnancy, Antiretroviral therapy, Latency, Antiretroviral treatment Background A cure for human immunodeficiency virus type-1 (HIV1) infection may hinge on understanding the mechanisms that allow HIV-1 to persist during otherwise effective antiretroviral treatment (ART). Studies of HIV-1 C2-V5 env and pol DNA and RNA sequences and integration sites during effective ART have shown multiple identical *Correspondence:
[email protected] 2 Seattle Children’s Research Institute, 1900 Ninth Ave, 8th Floor, Seattle, WA 98101, USA Full list of author information is available at the end of the article
env and pol templates (which we describe as “monotypic”) [1, 2], an increase in the proportion of monotypic env and pol proviruses over time [2, 3], and a linkage between monotypic env through the 3′ LTR proviral sequences with identical chromosomal integration sites [4], all indicating that HIV-infected cells proliferate. This study addressed our hypotheses that proliferation of HIV-1 infected CD4+ T-cells occurs at least in part by exposure to recall antigens, and that antigen-driven proliferation contributes to sustaining the HIV-1 reservoir. We took advantage of a H1N1 influenza vaccination study in HIV1-infected pregnant women to explore this hypothesis.
© The Author(s) 2017. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/ publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Wagner et al. AIDS Res Ther (2017) 14:7
Immunological responses to infections [5] and vaccines [6–8] have been associated with increases in HIV-1 plasma viral load, although the effect of influenza vaccination on plasma HIV-1 RNA has been variable [9–12]. The effect of vaccination on the proviral population has not been explored in detail. Studying responses to H1N1 influenza vaccination in pregnant HIV-infected, ART-treated, women who were vaccinated against H1N1 in last few months of 2009 provided a unique opportunity to explore the effect of recall antigen response on the HIV DNA population. The H1N1 pandemic strain emerged in the first few months 2009, and showed antigenic similarities to a strain that circulated in the human population in the mid 1970s [13]. As this strain presented neo-antigens to those born after the mid-1970s, including the study population of HIV-infected women, the study design presumed that participants with a pre-vaccination pandemic H1N1-specific antibody response had been infected and developed an immune response during the 2009 pandemic. However, because the pandemic H1N1 had approximately 70% homology at the T cell epitope level with recent seasonal H1N1 serotypes, very low pre-vaccination responses were considered due to cross-reactivity. Participants who were not on ART in the first half of 2009 during the H1N1 pandemic and had serologic evidence of infection with H1N1 antigens, were expected to have a recall response to the vaccination. Women who subsequently started ART should have proliferation of influenza-specific CD4+ memory T cells after vaccination, some of which would be latently infected with HIV-1. Increases in proviruses due to T-cell proliferation would cause an increase in the proportion of monotypic sequences in the viral population. In contrast, women on effective ART when they were infected with pandemic H1N1 or without pre-existing H1N1 antibody titers would not be expected to have evidence of proliferation of HIV-infected cells after H1N1 vaccination. To explore whether a response to a recall antigen leads to proliferation of HIV-1 infected cells, the HIV DNA from PBMC was quantified, multiple HIV-1 DNA genetic sequences were generated from each participant from before and after vaccination, and these sequences were analyzed for evidence of proliferation of HIV-infected cells. Because the timing of HIV diagnosis, ART, primary H1N1 antigen exposure, and subsequent H1N1 vaccination are well defined for this cohort, we had the potential opportunity to investigate the specific effect of antigendriven cell proliferation on HIV persistence during ART.
Methods This study utilized demographic and antibody data and specimens from HIV-1 infected pregnant women who had participated in a Phase II Study to Assess the Safety and Immunogenicity of an Inactivated Swine-Origin
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H1N1 Influenza Vaccine in HIV-1 Infected Pregnant Women (IMPAACT P1086) [14]. As part of P1086, participants’ blood was collected before and 21 days after the first H1N1 vaccination (high dose, 30 μg), at which time (21 days post primary vaccination) they received a H1N1 booster. Participants were selected for this substudy based on: (1) ART-suppression of HIV-1 replication (plasma HIV-1 RNA
