BALB/c小鼠免疫重组相思子毒素B链蛋白的免疫应答

摘要

Objective:To evaluate the immune response efficiency of the recombinant abrin B chain protein (rATB) in BALB/c mice.Methods:BALB/c mice were vaccinated intraperitoneally (i.p.) with the purified rATB protein.ELISA was used to detect the IgG,IgG1 and IgG2a.Meanwhile,the expression of IL-4 and IFN-γwere detected by flow cytometry.Then the protein neutralization assay and efficacy of passive protection were done .Results:The anti-rATB antibody was detected by ELISA after vaccinated the rATB in the mice and results showed that the highest titer reached 106 ,which was acquired after the last vaccination .Meanwhile,a strong secondary response was triggered in mice when challenged with toxin .In contrast ,the antibody response of the PBS-vaccinated mice was less than 1:10 and P<0.05 indicated obvious difference between test group and control group .The result of IgG 1 was the same as the IgG ,while the result of IgG2a had not changed.There was significant difference for IL-4 between two groups (P<0.05),while no significant difference for IFN-γwas observed.All BALB/c mice survived after challenged with 5×LD50 of AT.Transfusion of sera from immunized mice provided passive protection in naive mice.Furthermore, the rATB could induce specific neutralizing antibodies against abrin toxin.Conclusion: The recombinant protein can induce the Th 2-type immune response and trigger a good immune response and protective efficacy,which means it may be a promising vaccine candidate against human exposure to AT .%目的:评价重组相思子毒素B链蛋白(rATB)免疫雌性BALB/c小鼠的免疫效果,并初步探讨其免疫机制.方法:以rATB为免疫原,腹腔免疫雌性BALB/c小鼠,间接ELISA方法检测小鼠血清中IgG、IgG1、IgG2a,流式细胞技术检测IFN-γ、IL-4,并进行天然毒素攻毒实验和体外中和实验.结果:血清IgG、IgG1效价达到1:106以上,且攻毒后产生二次免疫应答,与PBS对照组差别有统计学意义(P<0.05);而IgG2a的血清效价未发生明显变化.细胞因子检测结果表明IFN-γ的表达量与PBS组差异无统计学意义,而IL-4的表达量显著提高(P<0.05).小鼠攻毒保护实验和体外中和实验结果说明,腹腔注射rATB可以抵抗最高剂量为5×LD50的天然AT毒素中毒,保护率为100%.结论:rATB蛋白免疫小鼠后显示出良好的免疫原性,能诱导以IgG1为主的抗体和Th2优势应答,为候选疫苗的研制奠定基础.