Expansion of HBV-specific memory CTL primed by dual HIV/HBV genetic immunization during SHIV primary infection in rhesus macaques

We have previously shown the induction of humoral and cytotoxic responses s pecific for human immunodeficiency virus (HIV) and hepatitis B virus (HBV) antigens, following genetic immunization of rhesus macaques with a plasmid encoding both the third variable domain of the HIV-1 external envelope glyc oprotein and the pseudo-viral particle of hepatitis B surface antigen (HBsA g) as presenting molecules. The DNA-immunized primates and two control anim als were then challenged with a chimeric simian/human immunodeficiency viru s (SHIV). They were all infected. Significant frequencies of SHIV specific cytotoxic T lymphocyte precursors (CTLp) were detected early in peripheral blood. But, in all DNA-immunized macaques, HBV envelope specific CTLp were detected during the primary infection, and they were correlated with the pe ak of SHIV viremia. Furthermore, HBV or SHIV specific cytotoxicity correspo nded in part to CD8(+) T cells presenting a memory phenotype. Several mecha nisms could account For this cellular response. But our results suggest tha t an expansion of memory cytotoxic CD8(+) cells, not restricted to SHIV spe cific effectors, could occur in peripheral blood during SHIV primary infect ion. (C) 2001 Elsevier Science Ltd. All rights reserved.