Identification Of A Conserved Universal Th Epitope In Hiv-1 Reverse Transcriptase That Is Processed And Presented To Hiv-Specific Cd4(+) T Cells By At Least Four Unrelated Hla-Dr Molecules

CD4(+) Th cells play an important role in the induction and maintenance of specific T cell immunity. Indications for a protective role of CD4(+) T cells against HIV-1 infection were found in subjects who were able to control HIV-1 viremia as well as in highly HIV-1-exposed, yet seronegative, individuals, This study describes the identification of an HIV-1-specific Th epitope that exhibits high affinity binding as well as high immunogenicity in the context of at least four different HLA-DR molecules that together cover 50-60% of the Caucasian, Oriental, and Negroid populations. This HIV-1 reverse transcriptase-derived peptide (RT171-190) is highly conserved among different HIV-1 isolates. Importantly, stimulation of PBL cultures from HIV-1 seronegative donors with this peptide resulted in Th1-type lymphocytes capable of efficient recognition of HIV-1-pulsed APCs, Taken together, these data indicate that peptide RT171-190 constitutes an attractive component of vaccines aiming at induction or enhancement of HIV-1-specific T cell immunity.