鼠疫疫苗在食蟹猴模型中的免疫学评价

The immunological evaluation of plague vaccine in cynomolgus monkeys

目的 通过将鼠疫耶尔森菌的F1抗原和重组V抗原组成的鼠疫疫苗免疫食蟹猴,对疫苗的免疫效果进行评价.方法 将20只食蟹猴按简单随机法分成低剂量组、高剂量组和生理盐水对照组,分别于0和2周肌内免疫,并于1剂后2周和2剂后2周采血.用ELISA检测免疫动物血清中的总IgG抗体;另外,分离外周血淋巴细胞,用酶联免疫斑点试验检测分泌IFN-γ的外周血淋巴细胞.用t检验对结果进行比较.结果 免疫后,对照组均未产生抗体,而疫苗组产生了较强的抗体应答.2剂免疫后2周,低、高剂量组的抗F1抗原IgG抗体几何平均滴度分别为（4.71±0.32）1g和（5.09±0.21）lg（t=-2.76,P＜0.05）,两组的抗重组V抗原IgG抗体几何平均滴度分别为（4.75±0.52） lg和（5.12±0.58） lg（t=-1.37,P＞0.05）.经F1和V抗原体外刺激产生IFN-γ的外周血淋巴细胞,细胞数均无明显增加.F1抗原刺激后,低、高剂量组分泌IFN-γ的外周血淋巴细胞数分别为（1±1）/106和（1±2）/106（t=-0.16,P＞0.05）.重组V抗原刺激后,两组分别为（7±15）/106和（6±7）/106（t=0.88,P＞0.05）.结论 鼠疫疫苗在食蟹猴模型中能诱导较强的体液免疫应答,但不能诱导明显的细胞免疫应答.

Objective To evaluate the immune effect of a new plague vaccine composed of Yersinia pestis F1 antigen and recombinant V （rV） antigen in cynomolgus monkeys.Methods Twenty cynomolgus monkeys were simply randomized into 3 groups and intramuscularly injected with low-dose plague vaccine,high-dose plague vaccine and saline at 0 and 2 weeks,respectively.The serum samples were collected 2 weeks after first and second immunization,examined for total IgG antibodies by ELISA.In addition,enzyme-linked irmunospot assay was used to detect IFN-γ-secreting lymphocytes in isolated peripheral blood lymphocytes.The results were compared by Student＆#39;s t-test.Results No IgG antibody was detected in the control group,but the plague vaccine induced strong antibody response In cynomolgus monkeys immunized with low-dose or high-dose vaccine,2 weeks after the second immunization,the geometric mean titers of anti-F1 IgG were （4.71 ± 0.32）lg and （5.09 ± 0.21）lg （t =-2.76,P 〈 0.05）,and anti-V IgG titers were （4.75 ± 0.52）1g and （5.12 ± 0.58）1g （t =-1.37,P 〉 0.05）,respectively.No significant increase of IFN-γ-secreting lymphocytes was found after in vitro stimulation with F1 and rV antigens.In cynomolgus monkeys immunized with low-dose or high-dose vaccine,when stimulated with F1,the number of IFN-γ-secreting cells was （1 ± 1）/106 and （1 ± 2）/106 （t =-0.16,P 〉 0.05）,respectively,and （7 ± 15）/106 and （6 ± 7）/106 （t =0.88,P 〉 0.05） when stimulated with rV.Conclusion Plague vaccine can elicit strong specific humoral response but weak cellular response in cynomolgus monkeys.