Abstract

Vibrio parahaemolyticus is one of the major pathogens responsible for vibriosis and zoonotic infections in teleosts, marine invertebrates, and also humans through consumption of contaminated or unprocessed seafood. Emergence of resistance against current accessible antibiotics and spread to the food chain and environment necessitate the development of safe and effective subunit vaccine against this bacterium. Many bacteria including V. parahaemolyticus produce extracellular curli fibrils, heteropolymeric filaments of major and minor subunit, which have been implicated in adhesion, biofilm formation, and virulence. Adhesins are the primary contact points with the host which help in establishing infection and colonization. CsgA, an adhesin, is the major structural component of the curli fiber that forms homopolymers of several hundred units. Due to their exposure on the cell surface, the curli fibers are recognized by the host’s immune system, would generate high immune response, and therefore can serve as effective vaccine candidate. In the present study, we describe characterization of the csgA gene, and preparation of recombinant soluble CsgA of V. parahaemolyticus (rVpCsgA), and evaluation of its vaccine potential. Immunization of BALB/c mice with the rVpCsgA mounted a strong immune response. Cellular immune assays such as antibody isotyping, in vitro splenocyte proliferation analysis, and cytokine profiling revealed mixed T-helper cell immune response. The anti-rVpCsgA antiserum was agglutination positive and specifically cross-reacted with the curli CsgA present on the outer membrane of V. parahaemolyticus cells, thus demonstrating its neutralization potential. One hundred percent survival of the immunized mice upon challenge with the lethal dosage of the bacterium established that the rVpCsgA could serve as an effective vaccine against the bacterium.

Key points

• Recombinant histidine-tagged CsgA of V. parahaemolyticus, rVpCsgA, was purified.

• The rVpCsgA immunization produced mixed immune response and agglutinating antibodies.

• Immunization with the rVpCsgA protected mice against V. parahaemolyticus challenge.

中文翻译：

---

重组CsgA（卷曲纤维的主要亚基）对副溶血性弧菌的免疫原性表征和保护功效

摘要

副溶血性弧菌是导致硬骨鱼，海洋无脊椎动物以及人类因食用受污染或未经加工的海鲜而引起弧菌病和人畜共患病感染的主要病原体之一。对当前可获得的抗生素的抗药性的出现以及其在食物链和环境中的传播，需要开发出针对这种细菌的安全有效的亚单位疫苗。许多细菌，包括副溶血性弧菌产生细胞外卷曲的原纤维，主要和次要亚基的杂聚合长丝，与粘附，生物膜形成和毒力有关。粘附素是与宿主的主要接触点，有助于建立感染和定植。CsgA是一种粘附素，是卷曲纤维的主要结构成分，可形成数百个单元的均聚物。由于卷曲蛋白纤维暴露在细胞表面，因此宿主的免疫系统可以识别它们，会产生高免疫应答，因此可以作为有效的疫苗候选物。在本研究中，我们描述了csgA基因的表征，以及副溶血弧菌（r VpCsgA），并评估其疫苗潜力。用r Vp CsgA免疫BALB / c小鼠会产生强烈的免疫反应。细胞免疫测定（例如抗体同型分型，体外脾细胞增殖分析和细胞因子谱分析）显示出混合的T辅助细胞免疫应答。抗r Vp CsgA抗血清凝集阳性，并与副溶血性弧菌细胞外膜上的卷曲CsgA发生特异性交叉反应，从而证明了其中和潜力。经用致死剂量的细菌攻击后，免疫小鼠的存活百分率证实了r Vp CsgA可以作为一种有效的抗细菌疫苗。

关键点

•纯化了溶血弧菌重组组氨酸标签的CsgA，rVpCsgA。

• rVpCsgA免疫产生了混合的免疫反应和凝集抗体。

•用rVpCsgA免疫可保护小鼠免受溶血性弧菌攻击。