Abstract: Objective To investigate the effects of immune responses induced by HIV-1 Nef recombinant overlapping peptides in mouse models.Methods BALB/c and C57BL/10 mice were immunized with HIV-1 Nef recombinant overlapping peptides and corresponding protein with 5 mice in each group. Spleen mononuclear cells (SMC) were isolated to detect specific cell responses by ELISPOT and flow cytometry. Large doses of Nef recombinant vaccinia virus challenge test was used to measure the protection of recombinant overlapping peptides to immunized mice.Results In C57BL/10 mice, ELISPOT results in adjuvant group were negative, LAI Nef-specific cellular immune responses in overlapping peptide group and the corresponding protein group were (145.7 ± 36.2) SFU/10⁶ SMC and (24.2 ± 10.2) SFU/10⁶ SMC respectively (P=0.001), (148.8 ± 50.4) SFU/10⁶ SMC and (19.8 ± 9.0) SFU/10⁶ SMC in BALB/c mice (P=0.004). NL4-3 Nef-specific cellular immune responses in overlapping peptide group and the corresponding protein group were (104.0 ± 33.8) SFU/10⁶SMC and (20.7 ± 9.5) SFU/10⁶ SMC (P=0.004) respectively. Percentage of Nef-specific CD₄⁺ and CD₈⁺ cells induced by recombinant overlapping peptides were 1.53 and 0.80. In virus challenge test, survival rates of overlapping peptide group, the corresponding protein group, adjuvant group and blank control group were 80%, 40%, 20% and 0% respectively. Conclusion Recombinant overlapping peptides can induce strong, protective, broad-spectrum specific cellular immune responses, with cross-reactive to different strains of Nef. Effects of immunization with recombinant overlapping peptide are stronger than those of the corresponding protein.

Key words: HIV Nef, recombinant overlapping peptide, immune protection, mouse