Antibody Maturation and Viral Diversification in HIV-Infected Women

Abstract

IntroductionThe Post-exposure Prophylaxis in Infants (PEPI)-Malawi trial evaluated infant antiretroviral regimens for prevention of post-natal HIV transmission. A multi-assay algorithm (MAA) that includes the BED capture immunoassay, an avidity assay, CD4 cell count, and viral load was used to identify women who were vs. were not recently infected at the time of enrollment (MAA recent, N = 73; MAA non-recent, N = 2,488); a subset of the women in the MAA non-recent group known to have been HIV infected for at least 2 years before enrollment (known non-recent, N = 54). Antibody maturation and viral diversification were examined in these women.MethodsSamples collected at enrollment (N = 2,561) and 12–24 months later (N = 1,306) were available for serologic analysis using the BED and avidity assays. A subset of those samples was used for analysis of viral diversity, which was performed using a high resolution melting (HRM) diversity assay. Viral diversity analysis was performed using all available samples from women in the MAA recent group (61 enrollment samples, 38 follow-up samples) and the known non-recent group (43 enrollment samples, 22 follow-up samples). Diversity data from PEPI-Malawi were also compared to similar data from 169 adults in the United States (US) with known recent infection (N = 102) and known non-recent infection (N = 67).ResultsIn PEPI-Malawi, results from the BED and avidity assays increased over time in the MAA recent group, but did not change significantly in the MAA non-recent group. At enrollment, HIV diversity was lower in the MAA recent group than in the known non-recent group. HRM diversity assay results from women in PEPI-Malawi were similar to those from adults in the US with known duration of HIV infection.ConclusionsAntibody maturation and HIV diversification patterns in African women provide additional support for use of the MAA to identify populations with recent HIV infection.

Analysis of HIV Diversity in HIV-Infected Black Men Who Have Sex with Men (HPTN 061)

“…This is consistent with our previous study where individuals with known recent infection had lower HRM scores than those with known non-recent infection [17]. The findings in this report provide further data supporting the use of the MAA to identify individuals with recent HIV infection for research studies [18]. …”

“…HIV diversification begins shortly after infection and is driven by a large viral population, short viral half-life, frequent viral recombination, and error-prone replication [22]. Higher HRM scores (i.e., higher levels of diversity) were observed in adults with a longer duration of HIV infection [17,18] and in older children [19,21], where age is a surrogate for the duration of infection. These findings are consistent with findings from other studies that analyzed HIV diversity using sequence-based measures [9,10].…”

HIV Diversity as a Biomarker for HIV Incidence Estimation: Including a High-Resolution Melting Diversity Assay in a Multiassay Algorithm

“…The diversity of viral populations may differ based on the route of HIV acquisition (33,34). However, our previous studies demonstrated that HRM scores from predominantly Caucasian MSM in the United States were very similar to those obtained from women in Africa (19); this suggests that differences in prevalent HIV subtypes, gender, race, and route of HIV acquisition may not present major obstacles to the use of the HRM diversity assay in MAAs for estimation of HIV incidence in other populations. Furthermore, the HIV incidence estimates obtained in this study using the HRMbased MAA are very similar to the longitudinal incidence estimates from cohorts with diverse study populations.…”

“…In this study, amplification failure in the initial PCR in the HRM diversity assay was very rare, and amplification failure for the nested PCR step was not observed for ENV1 or for five of the other seven regions evaluated. Amplification failure was also uncommon in other studies that used the HRM diversity assay to analyze samples from cohorts with subtype A, C, and D HIV infections (19,35,36). The HRM diversity assay in this study was performed using the LightScanner instrument, which was specifically designed for high-resolution melting analysis.…”

“…HRM scores correlate highly with diversity measures obtained from next-generation sequencing data (18). Previous studies have shown that the HRM diversity assay is useful for discriminating between recent and nonrecent infections (12,19). In this report, we evaluated whether the HRM diversity assay can be used in place of CD4 cell count testing as part of a 4-assay MAA without compromising the performance of the testing algorithm.…”