Immune responses following simian/human immunodeficiency virus (SHIV) challenge of rhesus macaques after human immunodeficiency virus (HIV)-1 third variable domain (V3) loop-based genetic immunization

Following DNA immunization of rhesus macaques with a plasmid encoding the h uman immunodeficieney virus (HIV)-1 third variable domain (V3) loop, presen ted by pseudo-viral envelope particles of hepatitis B virus, specific immun e responses were induced. The primates were then inoculated with a chimeric simian/human immunodeficiency virus (SHIV). All the animals were infected, but the V3-specific immunization provided a relative attenuation of the ac ute phase of infection in the absence of neutralizing antibody. In all anim als, SHIV-specific cytotoxic T-lymphocyte precursors (CTLp) were detected e arly in peripheral blood and lymph nodes. The viremia peak correlated signi ficantly with the decrease in CD4(+) T cells and with a transient increase in the percentage of natural killer cells. The infection induced an oligocl onalization of the CD8(+) T-cell variable beta chain repertoire in the bloo d. Surprisingly, HIV envelope-specific CTLp generated by genetic immunizati on may be governed by distinct circulation rules compared to SHIV-specific CTLp induced by infection.