ENHANCEMENT OF CELL-MEDIATED-IMMUNITY AGAINST HIV-1 INDUCED BY COINOCULATION OF PLASMID-ENCODED HIV-1 ANTIGEN WITH PLASMID EXPRESSING IL-12

Previous investigations have demonstrated that CTL may play an importa nt role in suppressing the disease progression of HIV infection. In th is study, we inoculated mice with IL-12 expression plasmid together wi th plasmid-encoding HIV-1 envelope to enhance CTL activity by activati ng a Th1-type response. The results of delayed-type hypersensitivity u sing the footpad swelling response and of CTL activity clearly showed that HIV-1-specific cell-mediated immunity was enhanced by inoculation of the IL-12 expression plasmid. Quantitation of cytokine in the sera of IL-12-inoculated mice revealed that IFN-gamma significantly increa sed. The enhanced cell-mediated immunity responses were abrogated by c ombined administration of the IL-12 expression plasmid and neutralizin g anti-IFN-gamma Ab. Together, these results suggest that enhanced vir us-specific cell-mediated immunity occurred via an endogeneously produ ced IFN-gamma by inoculation of IL-12 expression plasmid.