Cytotoxic T-lymphocyte cross-reactivity among different human immunodeficiency virus type 1 clades: implications for vaccine development.

AUTOR(ES)
RESUMO

Despite recent advances in antiviral therapy for human immunodeficiency virus (HIV) infection, successful global intervention will require an effective vaccine. Expanding evidence suggests that cytotoxic T-lymphocyte (CTL) responses will be an important component of such a vaccine. The varying geographic distribution of HIV type 1 (HIV-1) clades, with the relative absence of clade B HIV-1 outside the developed world, is considered a major obstacle to the development of a single efficacious vaccine. An understanding of cross-reactive CTL responses between different HIV-1 clades is crucial in the design of a vaccine which will be broadly immunogenic. In this study, we examined the ability of HIV-1 Gag-, reverse transcriptase-, and Env-specific CTL clones isolated from individuals infected in the United States to recognize non-B clade viral sequences and found that all were cross-reactive with the majority of non-B clade viral sequences tested. We next studied HIV-1-specific CTL responses in African individuals infected with clade A, C, or G virus and evaluated cross-recognition of clade B virus. Of 14 persons evaluated, all demonstrated cross-reactivity with the U.S. clade B viral constructs. We conclude that significant CTL cross-reactivity exists between clade B and non-B epitopes, suggesting that CTL cross-recognition among HIV-1 clades is more widespread than anticipated and that a vaccine based on a single clade may be broadly applicable.

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