Comparison of the early immune responses in mice vaccinated by different kinds of hepatitis B surface antigen
Objective To evaluate the early cellular immune responses to three kinds of hepatitis B surface antigen (HBsAg) in the immunized mice.Methods At day 4,the levels of IFN-γand IL-2 secreted by CD4+ and CD8+T cells which selected from splenic mononuclear cells (MNC) of the vaccinated mice were detected by enzyme-linked immunospot methods (ELISPOT) after stimulation in vitro with HBsAg MHC class Ⅰ peptide S28-39 of HBsAg or recombinant hepatitis B surface antigen(rHBsAg).Results After selected by MACs,the purity of CD3+/CD4+ and CD3+/CD8+T cell was more than 90％.The positive rate of IFN-γsecreted by CD4+T cells induced by HBsAg derived from Hansenula polymorpha(rHP) was higher than that of HBsAg derived from CHO cell (rCHO).Levels of IFN-γ secreted by CD8+T cells and IL-2 secreted by CD4+T cells induced by rHP antigen were significantly higher than those of rCHO( P＜0.05 ).Meanwhile,levels of IFN-γsecreted by CD4+T cells and CD8+T cells induced by rHP were also significantly higher than those of plasma HBsAg(pHB) (P＜0.05).Conclusion At day 4,the cellular immune responses induced by HBsAg could be detected.But the immune responses induced by the three kinds of HBsAg are different in levels.According to early cellular immune response intensity,the rHP HBsAg are superior to the rCHO and pHB,in accordance with the high protection rate interrupting the mother-infant transmission immunized by rHP vaccine in clinical trial.It provides scientific basis for necessity of timely birth dose of HB vaccine and kind of HB vaccine for high risk newborn infants vaccinated. 
 
Key words: 
Hepatitis B;  Surface antigen;  Cellular immune response;  Enzyme-linked immunospot ( ELISPOT )