Balb/C小鼠免疫重组蓖麻毒素与相思子毒素B链嵌合体蛋白的免疫应答

Immune response to a recombinant B chain chimeric protein of ricin and abrin in Balb/C mice

【目的】探讨重组蓖麻毒素、相思子毒素B链蛋白(RTB-ATB)免疫Balb/C小鼠的免疫机制。【方法】雌性Balb/C小鼠随机分为两组:RTB-ATB组和PBS组,分别腹腔免疫4次,间隔1周;间接ELISA检测血清中IgG效价和抗体分型,流式细胞技术检测细胞因子IFN-γ、IL-4,并进行攻毒实验和体外中和实验。【结果】四免后RTB-ATB组血清IgG、IgG1的效价与PBS对照组差别有统计学意义(P<0.05),而IgG2a未发生明显变化;IL-4的表达量RTB-ATB组与PBS组相比差别有显著性(P<0.05),而IFN-γ未发生变化(P>0.05)。攻毒保护实验和体外中和实验结果说明,嵌合体蛋白RTB-ATB可以抵抗4×LD50的天然AT或RT攻毒。【结论】RTB-ATB诱导以IgG1为主的抗体和Th2优势应答且显示出良好的免疫原性,为二价疫苗的研制奠定基础。

【Objective】To explore the immune mechanism of a recombinant B chain chimeric protein of ricin and abrin（RTB-ATB） in Balb/C mice.【Methods】The female Balb/C mice were randomly divided into two groups：RTB-ATB group and PBS group.The mice were treated with intraperitoneal（i.p.） immunization four times and an interval of one week.Ig titer and antibody typing in serum were detected by indirect ELISA.IFN-γ and IL-4 were detected by flow cytometry.Then the protein neutralization assay and efficacy of passive protection were done.【Results】Obvious difference in the serum titer of IgG and IgG1 was found between RTB-ATB group and PBS group（P〈0.05）,while there was no change in IgG2 a.Significant difference in the expression of IL-4 was also observed between two groups（P〈0.05）,while there was no change in IFN-γ（P〈0.05）.Meanwhile,all Balb/C mice survived after challenged with 4×LD50 of RT or AT in the tests of native toxin challenge and passive protection.【Conclusion】RTB-ATB can induce IgG1-based antibodies and Th2 dominant immune response.It shows good immunogenicity,which provides a foundation for the development of bivalent vaccine.