Heat shock protein 110 improves the immunological effect of an altered peptide ligand of human papilloma virus type 16 E711-20 peptide

Objective To investigate the adjuvant effect of heatshock protein 110 （HSP110） on the immune responses induced by an altered peptide ligand of human papilloma virus type 16 E711-20 peptide （HPV16E711-20）. Methods The complex of HSP110 and an altered peptide ligand of HPVI6ET11-20 was constructed in vitro. Fifteen 6-week-old C57BL/6 female mice were randomly and equally divided into 3 groups, including complex group, ligand group, and phosphate buffered solution （PBS） group, to receive intraperitoneal immunization with the complex （100 μg）, peptide （10 μg）, and PBS （100 μl） respectively. Immunization was carried out with an interval of 2 weeks for 2 times. Two weeks after the last immunization, the mice were sacrificed followed by the isolation of splenocytes. MTT assay was performed tO evaluate the proliferation activity of splenocytes, intracellular staining for interferon （INF）-γ to detect cytotoxic T lymphocytes （CTLs）, standard chromium-51 （53Cr） release assay to estimate the lethal effect of specific CTLs on target cells. Statistical analysis was performed by using t test with SPSS 10.0 software. Differences were considered as statistically significant when the P value was less than 0.05. Results A significant increase was observed in the proliferation index （1.87 ± 0.122 vs. 0.32± 0.071, t = 4.01, P 〈 0.01 ） of, and percentage of CD8qFN-γ＋ T lymphocytes （3.9% vs. 0.4%, t = 3.88, P 〈 0.01 ） among splenocytes from the complex group compared with the ligand group. At the effector-to-target ratio of 100 ： 1, 50 ： 1, 25 ： 1 and 12.5 ： 1, the death rate of target cells was 54.7%, 72.2%, 61.5% and 39.8% respectively after incubation with CTLs from the compleximmunized mice, higher than that from the ligand-immunized mice （35.2%, 49.3%, 28.1%, 17.4%, respectively）. Conclusion HSPll0 could enhance the immunological effect of the altered peptide ligand of HPV16E711-20, and can serve as an immunological adjuvant. Key words: HSP110 heat-shock proteins;  Human papillomavirus 16;  Altered peptide ligand