On The Effect Of Prothymosin α/Interleukin2Fusion Plasmid As An Immune Adjuvant

Interleukin2(IL-2), cytokine mainly secreted by activated Tlymphocytes, is often used as an adjuvant for adjuvant treatment of various diseases in clinical practice. However, due to its short half-life period, the dose should be increased to achieve the desired effects when used alone, which causes common toxic side effects. Prothymosina (proTa) helps IL-2produce better effect by regulating the LAK cytotoxicity induced by IL-2to reduce the side effects when IL-2is used alone. In order to research the feasibility of using ProTa/IL-2fusion plasmid as a vaccine adjuvant, Zhou FY and others built ProTa/IL-2fusion plasmid, adopting the gene recombination technology.In this study, we studied the immune enhancement of the ProTa/IL-2fusion plasmid that as a molecular adjuvant, we used ProTa/IL-2associated with pS2·S to immunize normal Balb/C and HBV transgenic mice by vivo electroporation transfection, and ran humoral immunity detections on mice blood drawn at different times. In the HBV Tg mice, another experimental group of different immunization strategies, peritoneal macrophages and spleen cells were taken to run detections on cellular immunity indicators.The results show that after the booster in Balb/C mice experiment, the antibody seroconversion rate of the pS2·S group is16/20and the OD450of antibody at14day(d) after immunization is (0.106±0.037), while28d is (0.177±0.094),35d(0.270±0.120),42d (0.426±0.207),49d (0.459±0.229) and56d(0.441±0.204), while antibody seroconversion rate of the group that combine with ProTa/IL-2is20/20, and OD450in14d is (0.213±0.140),28d is (0.456±0.148),35d(0.616±0.122),42d(0.697±0.089),49d(0.806±0.113) and56d is (0.862± 0.129), p<0.01. The results of the anti-HBs seroconversion expenriment show that,7days after immunity, the pS2·S group and the pS2·S+ProTa/IL-2group both have the seroconversion mice, OD450of pS2·S group is (0.111,0.106,0.056,0.069), while OD450of pS2·S&ProTa/IL-2group is (0.199,0.138,0.191,0.095);6days after immunity, the pS2·S&ProTa/IL-2group has2seroconversion-mice, OD450of which are0.106and0.120, while there is no seroconversion mice in the pS2·S group. The decline value of serum HBsAg OD450in42days after the booster of the combine ProTa/IL-2group is (0.134±0.016), while (0.048±0.010) in the pS2·S used alone group in HBV Tg mice experiments. The A570’s value of the phagocytic activity of peritoneal macrophage in the mouse of the combine whith the ProTa/IL-2group is (0.353±0.024), while (0.262±0.017) in the pS2·S used alone group, p<0.01. And the lymphocyte transformation rate in pS2·S used alone group is1.355, while1.526in another group, p<0.05. And induced lymphocyte to produce IL-2of higher titers, combine with ProTa/IL-2is (338.583±38.710) ng/L while (134.110±15.416) ng/L of the pS2·S used alone, p<0.01, also the IL-4of the group that combining with ProTa/IL-2is (166.03±32.82) ng/L while (71.06±21.06) ng/L of the pS2·S used alone, p<0.01. Elispot results show that the value of the lymphocytes to produce the specificity of IFN-y when associated ProTa/IL-2is (365.707±41.150), while (72.323±29.022) in the pS2·S used alone group, p<0.01. The results show that ProTa/IL-2can speed up and extend the time of the antibody production. It also can increase the antibody titers and enhance the phagocytic activity of peritoneal macrophage and lymphocyte transformation rate. Besides, it also can induce lymphocytes to produce the specificity of cytokines IL-2, IL-4and IFN-y.The above results show that the ProTa/IL-2can significantly strengthen the immune response induced by pS2·S.