PRIMING FOR VIRUS-SPECIFIC CD8-LYMPHOCYTES WITH SYNTHETIC LIPOPEPTIDEIS INFLUENCED BY ACYLATION UNITS AND LIPOSOME ENCAPSULATION( BUT NOT CD4+ CYTOTOXIC T)

Synthetic peptides of the herpes simplex virus glycoprotein B synthesi zed either as a free form or derivatized with one (PAMI) or three palm itic acids (PAM3Cys) were used to assess the in vivo priming efficacy of high affinity virus-specific CTL induction. The peptide and ifs der ivatives were delivered in vivo with or without liposome encapsulation . Neither the free peptide nor the PAMI derivative primed for high aff inity virus specific CD8+ CTL induction, whether delivered via liposom es or not. On the other hand the PAM3Cys derivative was able to prime for low levels of high affinity virus specific CD8+ CTL induction in t he absence of liposome encapsulation, However, the efficiency of virus -specific CD8+ CTL induction with PAM3Cys derivative was enhanced foll owing encapsulation in the liposomes. In contrast, all forms of the pe ptides induced both CD4+ T cell proliferative response as well as high affinity virus-specific CD4+ CTL. In addition, the efficiency of the PAM3Cys derivative to prime for CD4+ or CD8+ CTL was found to be influ enced by the liposome encapsulation. When delivered via liposomes, the PAM3Cys derivative effectively primed for CD8+ CTL. However, liposoma l delivery was not necessary for efficient priming for CD4+ CTL induct ion. Thus, both the acylation units as well as liposomal delivery appe ar to influence the in vivo priming of CD4+ and CD8+ T cell responses with synthetic peptides.