普氏立克次体120×10~3表面抗原的N端和C端重组蛋白免疫原性的研究

Immunogenicity of N-and C-terminal recombinant protein of 120×10^(3) surface antigen from Rickettsia prowazekii

目的:评价普氏立克次体120×103表面抗原的N端和C端重组蛋白的免疫原性。方法:将纯化的N端和C端重组蛋白分别免疫小鼠,采用酶联免疫吸附试验和间接免疫荧光试验分析免疫小鼠的体液免疫应答水平;用MTT法评价小鼠脾淋巴细胞的增殖情况,分析免疫小鼠的细胞免疫应答水平,并采用RT-PCR方法检测免疫小鼠脾淋巴细胞被重组蛋白刺激后细胞因子的表达。结果:N端和C端重组蛋白均诱导小鼠产生较高水平的特异性IgG抗体,诱导高水平的小鼠脾淋巴细胞增殖;经两种重组蛋白刺激的小鼠脾淋巴细胞均表达了IFN-γ和IL-2。结论:普氏立克次体120×103表面抗原的N端和C端重组蛋白具有良好的免疫原性,能够诱导机体产生高水平的体液免疫和细胞免疫应答,可作为流行性斑疹伤寒亚单位疫苗的候选蛋白。

Objective： To evaluate the immunogenicity of N- and C- terminal end recombinant proteins （rpN and rpC） of 120×10^3 surface protein from Rickettsia prowazekii. Methods：The BALB/c mice were immunized with the purified recombinant proteins rpN and rpC. The humoral immune responses of immunized mice were analyzed by detecting of the IgGs in sera with immunofluorescence assay （IFA） and enzyme-linked immunosorbent assay （ ELISA ） ; the splenic T cell proliferation of immunized mice was analyzed by MTF in order to evaluate cell-mediated immune responses. Results： The animals immunized with rpN or rpC exhibited profound humoral and cellular immunoresponses, including much higher levels of specific IgG antibodies and much stronger proliferation of splenic cells in response to homogenous antigen as compared with unimmunized mice. The expression of gamma interferon （IFN-γ） and interleukin-2 （IL-2） in splenic cells was demonstrated by RT-PCR. Conclusion： The recombinant proteins rpN and rpC may induce high levels of specific humoral and cellular immunoresponses, and may be the candidates of subunit vaccines against epidemic typhus.