Dynamic observation on splenocyte in mice immunized with recombinant Bi f idobacterium bi f idum (pGEX-S j26GST) of Schistosoma j aponicum / 中国人兽共患病学报

ABSTRACT

To observe the dynamic changes of splenocyte proliferation ,subsets and apoptosis in mice immunized with re-combinantBifidobacteriumbifidum(pGEX-Sj26GST)ofSchistosomajaponicum,themiceweresubcutaneously(SCgroup) and intranasally (IN group) immunized ,respectively .Four mice from each group were sacrificed in every 2 wk during 0-20 wk after immunization .Splenocyte proliferation was investigated by MTT colorimetric assay ,subsets of CD+4 and CD+8 T cells and apoptosis of splenocytes by FACsort flow cytometry .In SC group ,unstimulated and stimulated with S jAWA ,the level of splenocyte proliferation significantly increased at 4-20 wk after vaccination and increased markedly at 4-18 wk stimulated with ConA ,both of which peaked at 8 wk;in IN group ,the proliferation level of splenocyte cultured with SjAWA and ConA signif-icantly increased during the 4-18 wk ,2-10 wk and 14-18 wk ,2-8 wk and 12-18 wk ,respectively ,and all reached the maximum at the 4 wk after immunization (P＜0 .01 or P＜0 .05) .CD+4 subsets increased obviously during 2-14 wk ,2 wk and 6-16 wk re-spectively ,and reached the peak at 8 wk (P＜0 .01 or P＜0 .05) in both group ,while CD8+ subsets rose lightly during 2-20 wk in both group ,and reached the maximum at 8 wk (SC group) and 6 wk respectively (P>0 .05) .Whether unstimulated or stimulated with ConA ,the level of splenocyte apoptosis of which remarkably increased at 2-4 wk and 2-6 wk separately in SC group ,and both peaked at 2 wk (P＜0 .01 or P＜0 .05 );in IN group ,the level of splenocyte apoptosis all increased at 4 wk and reached the maximum at the same time .In summary ,by inducing the proliferation of splenocytes ,increasing CD4 + T cells and decreasing splenocyte apoptosis ,the rBb (pGEX-Sj26GST ) vaccine plays a critical role in the protective immune response .