新型肠炎沙门菌菌影候选疫苗在小鼠免疫应答和保护功效的评估

Immune responses to a novel Salmonella enteritidis ghost candidate vaccine and its protective efficacy in mice

目的比较肠炎沙门菌制备的菌影(SE-ghost)通过肌肉注射(肌注)和口服不同免疫途径接种雌性BALB/c小鼠诱导体液和细胞免疫应答的功效。方法用SE-ghost接种BALB/c小鼠,间接ELISA检测小鼠血清中IgG抗体水平和阴道灌洗液IgA抗体水平;流式细胞仪检测小鼠脾脏CD3^(+)CD4^(+)T、CD3^(+)CD8^(+)T细胞百分比变化和脾脏内细胞因子IL-4、IFN-γ分泌;三次免疫后所有小鼠口服半数致死量肠炎沙门菌进行强毒攻击。用SE-ghost刺激小鼠骨髓来源树突状细胞(BMDCs),流式细胞仪检测表面分子抗体APC-CD11c、FITC-MHC ClassⅡ、PE-CD40、FITC-CD86、PE-CD80表达量;双抗体夹心ELISA测定BMDCs上清液IL-1β、IL-6、IL-10和IL-12p70的产量。结果与PBS组相比,SE-ghost(口服)和SE-ghost(肌注)免疫组小鼠体内肠炎沙门菌特异性抗体IgG和IgA水平明显增高;脾脏CD3^(+)CD4^(+)T细胞百分比上调、高分泌细胞因子IL-4、IFN-γ。肌肉注射SE-ghost比口服可诱导更强的体液和细胞免疫应答。致病菌肠炎沙门菌强毒攻击后,SE-ghost(口服)和SE-ghost(肌注)免疫组生存率高达80%。与对照组相比,BMDCs经SE-ghost刺激后高表达表面成熟分子抗体CD86、CD80、CD40、MHCⅡ,高分泌细胞因子IL-1β、IL-6、IL-10、IL-12p70。结论通过肌肉注射SE-ghost进行免疫,可在小鼠中引发更强大的抗原特异性免疫应答,以防止沙门菌感染。SE-ghost是一种有用的沙门菌候选疫苗。

Objective To evaluate the humoral and cellular immune responses to Salmonella enteritidis ghost(SE-ghost)after intramuscular and oral administration in female BALB/c mice.Methods BALB/c mice were inoculated with SE-ghost.IgG antibody levels in serum and IgA antibody levels in vaginal lavage fluid were detected using indirect ELISA.The percentage of CD3^(+)CD4^(+)T and CD3^(+)CD8^(+)T cells and the secretion of IL-4 and IFN-γin spleen tissues were detected by flow cytometry.After three immunizations,all mice were challenged orally with half lethal dose of Salmonella enteritidis.SE-ghost was used to stimulate bone marrow-derived dendritic cells(BMDCs),and the expression of APC-CD11c,FITC-MHC ClassⅡ,PE-CD40,FITC-CD86 and PE-CD80 were detected by flow cytometry.The levels of IL-1β,IL-6,IL-10 and IL-12p70 in the supernatant of BMDCs were detected by double antibody sandwich ELISA.Results The levels of Salmonella enteritidis-specific IgG and IgA antibodies,the percentage of CD3^(+)CD4^(+)T cells and the levels of IL-4 and IFN-γwere higher in SE-ghost(oral)and SE-ghost(intramuscular)immune groups than in PBS group.Besides,oral administration of SE-ghost could induce strong humoral and cellular immune responses than intramuscular injection.the cytokines were highly secreted.The survival rates of mice in SE ghost(oral)and SE ghost(intramuscular)immune groups were as high as 80%after the challenge with Salmonella enteritidis.The expression of CD86,CD80,CD40 and MHCⅡand the secretion of IL-1β,IL-6,IL-10 and IL-12p70 by BMDCs were enhanced after SE-ghost stimulation.Conclusions Intramuscular injection of SE-ghost elicits a more robust Salmonella-specific immune response in mice.SE-ghost can be used as a candidate vaccine against Salmonella.