鼠疫F1-V重组蛋白疫苗滴鼻免疫应答效果的研究

Nasal immunization with plague F1-V recombinant protein mucosal vaccine induces systemic and mucosal immune responses in Balb/c mice

目的以重组霍乱毒素B亚单位(rCT-B)为鼠疫F1-V重组蛋白的佐剂制备黏膜疫苗,观察小鼠诱导的黏膜免疫和系统免疫应答效果。方法以制备的鼠疫黏膜疫苗滴鼻免疫小鼠4次免疫后,采用间接ELISA检测血清特异性抗F1-V的IgG和IgA抗体及抗体亚型分类,检测鼻咽喉、肺、小肠及阴道灌洗液中特异性抗F1-V的黏膜分泌型IgA;采用流式细胞术检测鼻相关淋巴组织淋巴细胞、脾淋巴细胞、肠系膜淋巴结及小肠PP结T淋巴细胞表型的变化。结果以rCT-B为佐剂的鼠疫F1-V重组蛋白黏膜疫苗滴鼻免疫后,能够诱导血清中IgGI、gA抗体比正常对照组显著升高(P<0.01),同时诱导鼻咽、肺、小肠和阴道内特异性黏膜抗体升高,尤其是肺和生殖道冲冼液内抗体升高极为显著(P<0.01)。与单纯的F1-V组相比,不同剂量比例疫苗组都能诱导较高、较快的血清IgGI、gA和黏膜sIgA,其中1∶2疫苗组能诱导更强的系统免疫和黏膜免疫,但是相比之下,5∶1疫苗组是最合适的免疫剂量。结论rCT-B佐剂不仅能提高鼠疫F1-V黏膜疫苗的系统全身免疫应答,还能促进诱导呼吸道、消化道和生殖道等局部黏膜sIgA抗体,增强局部免疫应答,提示rCT-B佐剂能显著提高鼠疫感染的免疫应答作用,这为下一步疫苗的免疫保护评价奠定了基础。

Objective To investigate the effects of plague recombinant protein F1-V mucosal vaccine on the mucosal and systemic immunity in mice. Methods Plague recombinant protein F1-V mucosal vaccine was produced by mixing plague F1-V recombinant antigen with the adjuvant rCT-B （recombinant cholera toxin unit B）. Balb/c mice were nasally immunized by the vaccine （once per week） for 4 weeks and sacrificed in week 5. The specific IgG and IgA to plague in sera of the mice were detected by indirect ELISA; the specific slgA to plague in nasal solution, lung solution, intestinal, and vaginal solution of the mice were detecting by ELISA; the cell phenotypes of inoculated or separated NALT, NP, spleens, PP nodes, and groin lymphocytes were detected by FACS. Results Intransal immunization of mice with rCT-B combined with plague recombinant protein F1-V significantly enhanced serum IgG and mucosal IgA levels compared with immunization with the antigens alone. The 5：1 formulation of plague mucesal vaccine was the optimal formulation for ehciting serum titers compared with other formulations. Conclusion Plague recombinant protein F1-V mucosal vaccine induce not only systemic immune response through enhancing the levels of IgG and IgA, but also mucesal immune response by increasing the level of slgA, which suggests that rCT-B could improve the effect of protective immunity against subsequent challenge infection of plague.