Observation of protective effect on mice after immunization with Yersinia pestis capsular antigen F1 and recombinant rV270 / 中国地方病学杂志

ABSTRACT

Objective To evaluate the protective effect of Yersinia pestis capsular antigen F1 and recombinant rV270 on mice after immunization with them.Methods According to body weight,40 female Balb/c mice aged 6 to 8 weeks were randomly divided into four experimental groups(Fl-10 μg + aluminum adjuvant,F1-20 μg + aluminum adjuvant,rV-10 μg + aluminum adjuvant,and rV-20 μg + aluminum adjuvant) and a control group,8 in each group.Mice in experimental groups were immunized with the natural antigen F1 and recombinant antigen rV270 adsorbed to 25％ aluminum adjuvant and the control group was immunized with the same amount of aluminum adjuvant.Each mouse was immunized at the hind leg muscle with 100 ml immunizing agent,then a booster immunization was done once on the 21st day after the first immunization.The blood of all mice was collected on the 8th week after the first immunization,serum antibody titers were detected by ELISA and the data of antibody titers were analyzed by t test for comparison between groups.At the same time the mice were injected subcutaneously with 2000-fold LD50 of Yersinia pestis virulent strain 141,after 14 days,the protective effect of immunization was analyzed.Results The control group did not produce antibody.Antibody geometric mean titers (GMT) of the F1-10 mg + aluminum adjuvant and F1-20 mg + aluminum adjuvant groups were 1 ∶ 30443.9,and 1 ∶21527.8,respectively,and compared between the two groups,the difference was not statistically significant (t =1.1282,P ＞ 0.05).The GMTs of the rV-10 μg + aluminum adjuvant and rV-20 μg + aluminum adjuvant groups were 1 ∶ 13957.3 and 1 ∶18100.9,respectively,and compared between the two groups,the difference was not statistically significant(t =0.9408,P ＞ 0.05 ).After subcutaneous injection with Yersinia pestis virulent strain 141,all mice died in the control group but all survived in the experimental group.Conclusion The immune activity of natural antigen F1 and recombinant rV270 is high,which can be used as the main component of subunit vaccine in the plague subunit vaccine study.