|Title||HIV Controllers Exhibit Enhanced Frequencies of Major Histocompatibility Complex Class II Tetramer(+) Gag-Specific CD4(+) T Cells in Chronic Clade C HIV-1 Infection.|
|Publication Type||Journal Article|
|Year of Publication||2017|
|Authors||Laher F, Ranasinghe S, Porichis F, Mewalal N, Pretorius K, Ismail N, Buus S, Stryhn A, Carrington M, Walker BD, Ndung'u T, Ndhlovu ZM|
|Date Published||2017 Apr 01|
Immune control of viral infections is heavily dependent on helper CD4(+) T cell function. However, the understanding of the contribution of HIV-specific CD4(+) T cell responses to immune protection against HIV-1, particularly in clade C infection, remains incomplete. Recently, major histocompatibility complex (MHC) class II tetramers have emerged as a powerful tool for interrogating antigen-specific CD4(+) T cells without relying on effector functions. Here, we defined the MHC class II alleles for immunodominant Gag CD4(+) T cell epitopes in clade C virus infection, constructed MHC class II tetramers, and then used these to define the magnitude, function, and relation to the viral load of HIV-specific CD4(+) T cell responses in a cohort of untreated HIV clade C-infected persons. We observed significantly higher frequencies of MHC class II tetramer-positive CD4(+) T cells in HIV controllers than progressors (P = 0.0001), and these expanded Gag-specific CD4(+) T cells in HIV controllers showed higher levels of expression of the cytolytic proteins granzymes A and B. Importantly, targeting of the immunodominant Gag41 peptide in the context of HLA class II DRB1*1101 was associated with HIV control (r = -0.5, P = 0.02). These data identify an association between HIV-specific CD4(+) T cell targeting of immunodominant Gag epitopes and immune control, particularly the contribution of a single class II MHC-peptide complex to the immune response against HIV-1 infection. Furthermore, these results highlight the advantage of the use of class II tetramers in evaluating HIV-specific CD4(+) T cell responses in natural infections.IMPORTANCE Increasing evidence suggests that virus-specific CD4(+) T cells contribute to the immune-mediated control of clade B HIV-1 infection, yet there remains a relative paucity of data regarding the role of HIV-specific CD4(+) T cells in shaping adaptive immune responses in individuals infected with clade C, which is responsible for the majority of HIV infections worldwide. Understanding the contribution of HIV-specific CD4(+) T cell responses in clade C infection is particularly important for developing vaccines that would be efficacious in sub-Saharan Africa, where clade C infection is dominant. Here, we employed MHC class II tetramers designed to immunodominant Gag epitopes and used them to characterize CD4(+) T cell responses in HIV-1 clade C infection. Our results demonstrate an association between the frequency of HIV-specific CD4(+) T cell responses targeting an immunodominant DRB1*11-Gag41 complex and HIV control, highlighting the important contribution of a single class II MHC-peptide complex to the immune response against HIV-1 infections.
|Alternate Journal||J. Virol.|
|PubMed Central ID||PMC5355603|
|Grant List||HHSN261200800001C / RC / CCR NIH HHS / United States |
HHSN261200800001E / CA / NCI NIH HHS / United States
R37 AI067073 / AI / NIAID NIH HHS / United States
UM1 AI100663 / AI / NIAID NIH HHS / United States
HIV Controllers Exhibit Enhanced Frequencies of Major Histocompatibility Complex Class II Tetramer(+) Gag-Specific CD4(+) T Cells in Chronic Clade C HIV-1 Infection.