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Specific human leukocyte antigens (HLAs), notably HLA-B*27 and HLA-B*57 allele groups, have long been associated with control of HIV-1. Although the majority of HIV-specific [CD8.sup.+] T cells lose proliferative capacity during chronic infection, T cells restricted by HLA-B*27 or HLA-B*57 allele groups do not. Here we show that [CD8.sup.+] T cells restricted by 'protective' HLA allele groups are not suppressed by [T.sub.reg] cells, whereas, within the same individual, T cells restricted by 'nonprotective' alleles are highly suppressed ex vivo. This differential sensitivity of HIV-specific [CD8.sup.+] T cells to [T.sub.reg] cell-mediated suppression correlates with their expression of the inhibitory receptor T cell immunoglobulin domain and mucin domain 3 (Tim-3) after stimulation with their cognate epitopes. Furthermore, we show that HLA-B*27- and HLA-B*57-restricted effectors also evade [T.sub.reg] cell-mediated suppression by directly killing [T.sub.reg] cells they encounter in a granzyme B (GzmB)-dependent manner. This study reg uncovers a previously unknown explanation for why HLA-B*27 and HLA-B*57 allele groups are associated with delayed HIV-1 disease progression., Cytotoxic T lymphocytes (CTLs) are crucial in controlling HIV-1 infection (reviewed in ref. 1), which is emphasized by the influence of human leukocyte antigen (HLA) class I alleles on the [...]

Specific human leukocyte antigens (HLAs), notably HLA-B*27 and HLA-B*57 allele groups, have long been associated with control of HIV-1. Although the majority of HIV-specific CD8+ T cells lose proliferative capacity during chronic infection, T cells restricted by HLA-B*27 or HLA-B*57 allele groups do not. Here we show that CD8+ T cells restricted by 'protective' HLA allele groups are not suppressed by Treg cells, whereas, within the same individual, T cells restricted by 'nonprotective' alleles are highly suppressed ex vivo. This differential sensitivity of HIV-specific CD8+ T cells to Treg cell-mediated suppression correlates with their expression of the inhibitory receptor T cell immunoglobulin domain and mucin domain 3 (Tim-3) after stimulation with their cognate epitopes. Furthermore, we show that HLA-B*27- and HLA-B*57-restricted effectors also evade Treg cell-mediated suppression by directly killing Treg cells they encounter in a granzyme B (GzmB)-dependent manner. This study uncovers a previously unknown explanation for why HLA-B*27 and HLA-B*57 allele groups are associated with delayed HIV-1 disease progression. [ABSTRACT FROM AUTHOR]

Most T cell-based HIV-1 vaccine candidates induce responses of limited breadth for reasons that are unclear. We evaluated vaccine-induced T-cell responses in individuals receiving an HIV-1 recombinant adenoviral vaccine. Certain HLA alleles (B27, B57, B35, and B14) are preferentially utilized to mount HIV-specific responses, whereas other alleles (A02 and B07) are rarely utilized (P < 0.001). This preference seems due to 4 following factors individually or in combination: higher affinity of specific peptides to specific HLA alleles; higher avidity of T-cell receptor; HLA and peptide interaction; and/or higher surface expression of certain HLA. Thus, HLA immunodominance plays a substantial role in vaccine-induced T-cell responses.

HLA alleles B57/58, B27, and B35 have the strongest genetic associations with HIV-1 disease progression. The mechanisms of these relationships may be host control of HIV-1 infection via CD8(+) T-cell responses. We examined these immune responses in subjects from the Seattle Primary Infection Cohort with these alleles. CD8(+) T-cell responses to conserved HIV epitopes within B57/58 alleles (TW10 and KF11) and B27 alleles (KK10 and FY10) delayed declines in CD4(+) T-cell counts (4 to 8 times longer), while responses to variable epitopes presented by B35 alleles (DL9 and IL9) resulted in more rapid progression. The plasma viral load was higher in B57/58(+) and B27(+) subjects lacking the conserved B57/58- and B27-restricted responses. The presence of certain B57/58-, B27-, and B35-restricted HIV-specific CD8(+) T-cell responses after primary HIV-1 infection better defined disease progression than the HLA genotype alone, suggesting that it is the HIV-specific CD8(+) T cells and not the presence of a particular HLA allele that determine disease progression. Further, the most effective host CD8(+) T-cell responses to HIV-1 were prevalent within an HLA allele, represented a high total allele fraction of the host CD8(+) T-cell response, and targeted conserved regions of HIV-1. These data suggest that vaccine immunogens should contain only conserved regions of HIV-1.