Objective FSM 2117,FS 5416,FS 5414,FS 5411 and FS 5402 are two types of bivalent hybrid strains of S. flexneri and
S. sonnei, constructed by our laboratory, The FS 5416,FS 5414,FS 5411 and FS 5402 express four invasive plasmid antigens and can be invasive to Hela cells(inv+), but the FSM 2117 does not(inv-). To observe the differences of the two types of bivalent shigella vaccines in immune responses and memory responses, we detected the antibodies of shi gella flexneri and sonnei LPS after three times immunization and boosting immunization after 20 weeks.Methods Using the ELISA assay, the changes of
specific antibodies of mice (the levels of SIgA and IgG) were detected after immunization with five different vaccines and boosting immunization after an interval of 20 weeks. Results We observed significant rises in different mucosal sites wash and serum on the two times immunization.Significant differences were observed between two immunized groups and the control. Both of the two types of bivalent shigella vaccines showed
memory response, but the levels of antibodies were lower than that of the third immunization. Conclusion Two types of shigella vaccines can induce antigen specific antibodies not only in several mucosal sites but also in serum after three times immunization. They can arose the memory immune responses not only in local nasal site but also in the other mucosal sites and serum. The expression of invasive plasmid antigens can improve the level of antibodies immune responses and the memory responses.