Cross-reactive cytotoxic T lymphocytes induced by V3 loop synthetic peptides from different strains of human immunodeficiency virus type 1.

Recent efforts at understanding the immune response generated against human immunodeficiency virus (HIV) infection have focused on cytotoxic T lymphocyte (CTL)-mediated recognition of HIV antigens. CTLs are a major immune defense mechanism and are necessary for the recovery of many viral infections. We have previously developed a method for screening synthetic peptides for the ability to induce virus-specific major histocompatibility complex-restricted CTLs in mice. Using this method, we now report the identification of peptides from the V3 region in gp120 of seven different HIV-1 strains that are capable of inducing a virus-specific CD8+ CTL response in vivo. V3 peptides from MN and SC strains of HIV-1, which are representative of typical strains found in North America and Europe, induced CTLs that exhibited cross-reactivity against a broad range of HIV-1 strains. In addition, immunization of mice with a mixture of these V3 peptides resulted in efficient CTL responses directed against the corresponding HIV-1 strains. These data, together with information in the literature describing the CTL epitope nature of V3 peptide from HIV-1 IIIB in the context of several HLA alleles, indicate the possibility of including V3 synthetic peptides as components of potential vaccines for inducing broadly cross-reactive CTL response against a diverse array of HIV-1 strains.