日本血吸虫重组Bb(pGEX-Sj26GST)疫苗免疫BALB/c小鼠脾细胞动态观察

Dynamic observation on splenocyte in mice immunized with recombinant Bifidobacterium bifidum (pGEX-Sj26GST) of Schistosoma japonicum

目的观察日本血吸虫重组Bb（pGEX—Sj26GST）疫苗免疫BALB／c小鼠后脾细胞增殖、亚群和凋亡的动态变化。方法将疫苗分别经皮下注射（SC组）和鼻腔粘膜接种（IN组）免疫BALB／c鼠，在免疫后O～22周每2周每组随机剖杀4只小鼠，无菌取脾，制成单个悬浮脾细胞，用四甲基偶氮唑盐比色法（MTT法）检测脾细胞增殖水平、用流式细胞仪（FACsort）检测T细胞亚群和脾细胞凋亡状况。结果未刺激及sjAWA刺激时SC组小鼠脾细胞增值水平于免疫后4～20周明显升高，ConA刺激时于4～18周显著升高，均于免疫后8周达最高水平；IN组脾细胞增殖水平原液组、SjAwA组和ConA组分别于2～18周、2～10周及14～18周、2～8周和12～18周显著升高，均于免疫后4周达最大值（P〈0．01或P〈0．05）。SC组和IN组CD＋T细胞分别于免疫后2～14周、2周及6～16周升高，并于8周达峰值（P〈0．01或P〈0．05）；两组CD＋T细胞均于2～20周轻微升高，分别于8周和6周达较高值（P〉0．05）。未刺激和ConA刺激时SC组脾细胞凋亡水平分别于免疫后2～4周、2～6周升高显著，均于免疫后2周达最大值（P〈O．01或P〈O．05）；IN组均于4周显著升高并达峰值（P〈O．01）。结论日本血吸虫重组Bb（pGEX-Sj26GST）疫苗可诱导脾细胞的增殖，增加cD＋T细胞的数目，抑制脾细胞的凋亡而发挥保护性免疫应答。

To observe the dynamic changes of splenocyte proliferation, subsets and apoptosis in mice immunized with re- combinant Bifidobacterium bifidum （pGEX-Sj26GST） of Schistosoma japonicurn, the mice were subcutaneously （SC group） 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＋ and CD＋ T cells and apoptosis of splenocytes by FACsort flow cytometry. In SC group, unstimulated and stimulated with SjAWA, 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）. CD4^＋ 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 cellsand decreasing splenocyte apoptosis, the rBb （pGEX-Sj26GST） vaccine plays a critical role in the protective immune response.