Hays Michael P, Kumar Amit, Martinez-Becerra Francisco J, Hardwidge Philip R
College of Veterinary Medicine, Kansas State University Manhattan, KS, USA.
Immunology Core Laboratory of the Kansas Vaccine Institute and Department of Pharmaceutical Chemistry, University of Kansas Lawrence, KS, USA.
Front Cell Infect Microbiol. 2016 Dec 12;6:181. doi: 10.3389/fcimb.2016.00181. eCollection 2016.
Achieving cross-protective efficacy against multiple bacterial strains or serotypes is an important goal of vaccine design. Enterotoxigenic (ETEC) is an important cause of diarrheal disease in underdeveloped nations. We have been interested in identifying and characterizing ETEC antigens that generate protective immune responses independent of ETEC colonization factor (CF) expression. Our previous studies used proteomics to identify the ETEC MipA, Skp, and ETEC_2479 proteins as effective in protecting mice from homologous challenge with ETEC H10407 using a pulmonary inoculation model. This model permits analysis of mouse survival, bacterial clearance, and the production of secretory IgA (sIgA) and has been employed previously for studies of enteric pathogens for which robust oral challenge models do not exist. MipA belongs to a family of proteins involved in remodeling peptidoglycan. Skp rescues misdirected outer membrane proteins. ETEC_2479 is predicted to function as an outer membrane porin. These proteins are conserved in pathogenic ETEC strains as well as in commensal . Antibodies produced against the ETEC MipA, Skp, and ETEC_2479 proteins also reduced the adherence of multiple ETEC strains differing in CF type to intestinal epithelial cells. Here we characterized the ability of 10 heterologous ETEC strains that differ in CF type to cause clinical signs of illness in mice after pulmonary challenge. ETEC strains C350C1A, E24377A, E7476A, WS2173A, and PE360 caused variable degrees of lethality in this mouse model, while ETEC strains B7A, WS6866B, 2230, ARG-2, and 8786 did not. Subsequent challenge experiments in which mice were first vaccinated intranasally with MipA, Skp, or ETEC_2479, when combined with cholera toxin, showed both that each antigen was protective and that protection was strongly correlated with fecal IgA concentrations. We conclude that the MipA, Skp, or ETEC_2479 antigens generate protection in the mouse pulmonary challenge model against ETEC strains that express different CFs.
实现针对多种细菌菌株或血清型的交叉保护效力是疫苗设计的一个重要目标。产肠毒素大肠杆菌（ETEC）是欠发达国家腹泻病的一个重要病因。我们一直致力于鉴定和表征能产生独立于ETEC定植因子（CF）表达的保护性免疫反应的ETEC抗原。我们之前的研究利用蛋白质组学鉴定出ETEC MipA、Skp和ETEC_2479蛋白在使用肺部接种模型保护小鼠免受ETEC H10407同源攻击方面是有效的。该模型允许分析小鼠存活率、细菌清除情况以及分泌型IgA（sIgA）的产生，并且之前已用于不存在强大口服攻击模型的肠道病原体研究。MipA属于参与重塑肽聚糖的蛋白质家族。Skp可挽救错误定位的外膜蛋白。预测ETEC_2479具有外膜孔蛋白的功能。这些蛋白在致病性ETEC菌株以及共生菌中都是保守的。针对ETEC MipA、Skp和ETEC_2479蛋白产生的抗体也降低了不同CF类型的多种ETEC菌株对肠上皮细胞的黏附。在此，我们表征了10种CF类型不同的异源ETEC菌株在肺部攻击后在小鼠中引起疾病临床症状的能力。ETEC菌株C350C1A、E24377A、E7476A、WS2173A和PE360在该小鼠模型中导致了不同程度的致死率，而ETEC菌株B7A、WS6866B、2230、ARG - 2和8786则没有。随后的攻毒实验中，当小鼠首先经鼻接种MipA、Skp或ETEC_2479并联合霍乱毒素时，结果表明每种抗原都具有保护作用，并且保护作用与粪便IgA浓度密切相关。我们得出结论，MipA、Skp或ETEC_2479抗原在小鼠肺部攻击模型中对表达不同CFs的ETEC菌株产生保护作用。
