STRONG AUGMENT EFFECT OF IL-12 EXPRESSION PLASMID ON THE INDUCTION OFHIV-SPECIFIC CYTOTOXIC T-LYMPHOCYTE ACTIVITY BY A PEPTIDE VACCINE CANDIDATE

We previously reported that repeated inoculation of VC1, a macromolecu lar multicomponent peptide vaccine emulsified with Freund's adjuvant ( VC1-F), induced high cytotoxic T lymphocyte (CTL) levels and a substan tial level of multivalent antibodies which neutralized various human i mmunodeficiency virus type 1 (HIV-1) isolates, In the present study, w e report that inoculation of VC1-F plus interleukin (IL)-12 expression plasmid can induce a higher antigen-specific CTL response comparied t o that with VC1-F alone. VC1-F plus IL-12 expression plasmid or VC1-F alone were inoculated to BALB/c mice twice at interval of 2 weeks. Two weeks after the second inoculation, spleen effector cells from these mice were examined. Stronger CTE responses against target cells were o bserved from the inoculation of VC1-F plus IL-12 plasmid than from tha t with VC-IF alone, but there was no difference in antibody induction. The inoculation of VC1 plus IL-12 plasmid also producted higher CTL a ctivity than the inoculation of VC1 alone. These augmented CTL activit ies were not observed using target cells pulsed with non-HIV-specific peptides and different class I haplotype cells, These data demonstrate that co-inoculation of cell-mediated immune potent antigen and IL-12 plasmids can enhance the antigen-specific CTL response. This may be a potential approach for the induction of cellular immunization against HIV-1 and Other diseases. (C) 1997 Academic Press.