IL-12,IL-18 gene modulates immune responses induced by HIV-1 envelope nucleic acid vaccine
Objective To investigate the effect of IL-12, IL-18 gene immunization on immune response induced by HIV-1 co-administered envelope nucleic acid vaccine(DNA vaccine) and to explore new strategies for HIV-1 envelope nucleic acid vaccine. Methods BALB/c mice were immunized with pVAX1GP120 alone or with the DNA encoding for IL-12, IL-18. Their sera were collected for analyzing anti-HIV antibody and IFN-γ by ELISA, and splenocytes were isolated for detecting antigen-specific lymphoproliferative responses and specific CTL response by MTT assay and LDH assay respectively. Results The anti-HIV antibody titers of mice co-immunized with pVAX1GP120 and the DNA encoding for IL-12, IL-18 were lower than that of mice immunized with pVAX1GP120 alone(P0.01). The IFN-γ level of mice co-immunized with pVAX1GP120 and the DNA encoding for IL-12, IL-18 was higher than that of mice immunized with pVAX1GP120 alone(P0.01). Furthermore, compared with mice injected with pVAX1GP120 alone, the specific CTL cytotoxity activity and antigen-specific lymphoproliferative responses of mice immunized with pVAX1GP120 and the DNA encoding for IL-12, IL-18 were significantly enhanced respectively (P0.01). Conclusion The DNA encoding for IL-12, IL-18 together with HIV DNA vaccine may enhance specific T_H1 responses and cellular immune responses elicited in mice. Moreover, the DNA encoding for IL-12, IL-18 may down-regulate the humoral responses. Hence the DNA encoding for IL-12, IL-18 are potential immune adjuvants for therapeutic HIV DNA vaccine.