Effects of different doses of interleukin 2 as adjuvants on immune responses induced by nucleic acid vaccines of hepatitis B virus

doi:10.3969/j.issn.1000-8861.2001.01.007

Abstract：Objective To construct recombinant plasmids of pCR3.1-S encodingprotein S of hepatitis B virus as nucleic acid vaccines and investigate the effects of recombinant human interleukin 2 as adjuvants on immune responses induced by HBV nucleic acid vaccines in BALB／c mice. Methods Anti-HBs antibodies to HBV major protein was measured by ELISA assay， and the activities of lymphocyte proliferation and cytotoxity were detected by 3H-TdR incorporation assay and 4-hour 51Cr release assay. Humoral and cellular immune responses of different groups were then compared. Results The titers of anti-HBs antibodies in serum of rhIL-2 group mice were not significantly higher than those of control group mice （P＞0.05）． The difference of the activities of lymphocyte proliferation and cytotoxity between of control group mice and rhIL-2 group mice （every mouse with 500 U one time） was not significant （P＞0.05）． However， stimulation index and specific lysis rate of lymphocyte of rhIL-2 group mice （every mouse with 1 000 U or 2 000 U one time） showed significant difference compared with htose of control group mice （P＜0.05）． Conclusion Recombinant plasmids of pCR3.1-S as HBV nucleic acid vaccines could induced strong humoral and cellular immune responses in BALB／c mice. rhIL-2 acts as adjuvants to increase the potency of HBV nucleic acid vaccine in some certainty.