鼠疫溶菌疫苗免疫小鼠的体液免疫应答

Humoral immune responses in mice immunized with the whole cell lysate of Yersinia pestis vaccine

为选择以F1抗原为主要有效成分的鼠疫溶菌疫苗(Whole cell lysate of Yersinia pestis vaccine,WCLY)的免疫程序,设计了这组试验。在37℃培养鼠疫EV菌,通过超声波裂解法制备鼠疫溶菌疫苗。设计(0,2周)、(0,4周)、(0,2,4周)三种免疫程序,以每剂总蛋白量7.9μg、31.5μg和126.0μg三个剂量皮下接种NIH小鼠。分别在第一针免疫后2、4、8、12周采集血清,通过间接ELISA检测抗鼠疫菌F1抗原和总抗原抗体。结果显示:免疫后血清抗体上升很快,2周内即可测出;无论哪种免疫程序,至12周时抗体滴度仍保持高水平;加强免疫后,抗体水平在4周或8周达到较高,可与活疫苗免疫者相比;溶菌疫苗的接种剂量为7.9μg时,动物只出现轻度不良反应。提示鼠疫溶菌疫苗需要两剂免疫,最短可间隔2周,接种剂量应不超过7.9μg,疫苗中应富含F1抗原。

In order to determine immunization schedules of the whole cell lysate of Y. pestis （WCLY） vaccine which contained the F1 antigen as the main active ingredients, this experiment was designed. The attenuated Y. pestis strain （ EV ） , which has been used for plague vaccine, was incubated at 37℃ for 48 h and harvested. WCLY vaccine was prepared through ultrasonieation, centrifugation and filtration of the bacterial liquid. Three regimens （ 0, 2 week ）, （0, 4 week ） and （ 0, 2, 4 week ） were designed and NIH mice were immunized subcutaneously with WCLY vaccine at 3 different dosages. After the priming dose, blood samples were obtained at 2, 4, 8 and 12 week, respectively. Indirect ELISA was used to determine the level of F1 antibody and total IgG titers of Y. pestis. The results showed that the serum antibody increased rapidly. It could be measured within 2 weeks and the IgG titers remained high level up to 12 week whatever the immunization schedules. Additionally, the titers could be comparable to that of live attenuated Y. pestis vaccine and rose higher after booster at 4 week or 8 week. Meanwhile, the animals appeared slight systemic and local side-effects with dosage 7.9 g. Conclusion： First, two-dose administration was necessary and the shortest interval could be 2 weeks. Second, the dosage should be not more than 7.9 g and the WCLY vaccine should be rich in F1 antigen. Key words： Yersinia pestis; Whole cell lysate vaccine; Attenuated live Yersinia pestis vaccine; Humoral immune responses