Heterogeneity in the recognition of the simian immunodeficiency virus envelope glycoprotein by CD4+ T cell clones from immunized macaques.

CD4+ T cell recognition of the simian immunodeficiency virus (SIV) surface envelope (env) glycoprotein was examined by using a panel of 10 T cell lines and 4 T cell clones derived from 10 individual macaques immunized with inactivated SIV or recombinant SIV env proteins. The results demonstrated that CD4+ T cells from each animal recognized between 1 and 7 peptides in 4 distinct regions of the protein including both variable and conserved domains. MLR of PBMC from selected macaques together with RFLP analysis by using the HLA DR beta probes suggested that animals of distinct MHC class II haplotypes can recognize identical peptides. These T cell epitopes within conserved regions of the envelope protein, together with identified linear B cell epitopes recognized by neutralizing antibodies, may be relevant in vaccine design.