1. Frequencies of Circulating Th1-Biased T Follicular Helper Cells in Acute HIV-1 Infection Correlate with the Development of HIV-Specific Antibody Responses and Lower Set Point Viral Load.
- Author
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Baiyegunhi O, Ndlovu B, Ogunshola F, Ismail N, Walker BD, Ndung'u T, and Ndhlovu ZM
- Subjects
- Acute Disease, Adult, CD4 Lymphocyte Count, Female, HIV Antibodies blood, HIV Infections blood, HIV Infections pathology, HIV-1 metabolism, Humans, Immunoglobulin G blood, Male, Th1 Cells metabolism, Th1 Cells pathology, Antibody Formation, HIV Antibodies immunology, HIV Infections immunology, HIV-1 immunology, Immunoglobulin G immunology, Th1 Cells immunology, Viral Load
- Abstract
Despite decades of focused research, the field has yet to develop a prophylactic vaccine for HIV-1 infection. In the RV144 vaccine trial, nonneutralizing antibody responses were identified as a correlate for prevention of HIV acquisition. However, factors that predict the development of such antibodies are not fully elucidated. We sought to define the contribution of circulating T follicular helper (cTfh) subsets to the development of nonneutralizing antibodies in HIV-1 clade C infection. Study participants were recruited from an acute HIV-1 clade C infection cohort. Plasma anti-gp41, -gp120, -p24, and -p17 antibodies were screened using a customized multivariate Luminex assay. Phenotypic and functional characterizations of cTfh cells were performed using HLA class II tetramers and intracellular cytokine staining. In this study, we found that acute HIV-1 clade C infection skewed the differentiation of functional cTfh subsets toward increased Tfh1 ( P = 0.02) and Tfh2 ( P < 0.0001) subsets, with a concomitant decrease in overall Tfh1-17 (which shares both Tfh1 and Tfh17 properties) ( P = 0.01) and Tfh17 ( P < 0.0001) subsets, compared to the subsets found in HIV-negative subjects. Interestingly, the frequencies of Tfh1 cells during acute infection (5.0 to 8.0 weeks postinfection) correlated negatively with the set point viral load ( P = 0.03, Spearman rho [ r ] = -60) and were predictive of p24-specific plasma IgG titers at 1 year of infection ( P = 0.003, r = 0.85). Taken together, our results suggest that the circulating Tfh1 subset plays an important role in the development of anti-HIV antibody responses and contributes to HIV suppression during acute HIV-1 infection. These results have implications for vaccine studies aimed at inducing long-lasting anti-HIV antibody responses. IMPORTANCE The HIV epidemic in southern Africa accounts for almost half of the global HIV burden, with HIV-1 clade C being the predominant strain. It is therefore important to define immune correlates of clade C HIV control that might have implications for vaccine design in this region. T follicular helper (Tfh) cells are critical for the development of HIV-specific antibody responses and could play a role in viral control. Here we showed that the early induction of circulating Tfh1 cells during acute infection correlated positively with the magnitude of p24-specific IgG and was associated with a lower set point viral load. This study highlights a key Tfh cell subset that could limit HIV replication by enhancing antibody generation. This study underscores the importance of circulating Tfh cells in promoting nonneutralizing antibodies during HIV-1 infection., Competing Interests: We declare no conflict of interest., (Copyright © 2018 American Society for Microbiology.)
- Published
- 2018
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