Subramanian K, Shankar R B, Meenakshisundaram S, Lakshmi B S, Williams P H, Balakrishnan A
Centre for Biotechnology, Anna University, Chennai, India.
J Appl Microbiol. 2008 Sep;105(3):715-22. doi: 10.1111/j.1365-2672.2008.03800.x. Epub 2008 Apr 4.
To establish the role of maltoporin (LamB) in adherence of enteropathogenic Escherichia coli (EPEC) to epithelial cells in vitro.
Three strains, wild type (WT) EPEC, a maltoporin (LamB) mutant DeltalamB, and DH5alpha were used to study adherence to cultured HEp-2 cells. Mutant DeltalamB was found to be deficient in adherence compared to WT EPEC. Adherence of DeltalamB was restored to wild type levels when complemented with the cloned lamB gene. The non-adherent strain DH5alpha also adhered to HEp-2 cells when it harboured the cloned lamB gene. The LamB protein was isolated from WT EPEC by electroelution and antibodies were raised in rabbits. The specificity of the antibodies was analysed by Western blotting. Anti-LamB antiserum reduced adherence of WT EPEC to HEp-2 cells. The LamB protein was coated on latex beads and the beads adhered to HEp-2 cells. Anti-LamB antiserum prevented bead adherence to HEp-2 cells. Multiple sequence alignment showed that the L9 loop of EPEC LamB had four amino acids different from the L9 loop of LamB from several other related pathogens.
LamB serves as an alternative or additional adherence factor for EPEC.
Adherence is an important component of the pathogenesis of noninvasive pathogens like EPEC. A putative adhesin such as LamB, which has already been found to be co-expressed with virulence factor EspB may be a potential vaccine candidate for control of EPEC and related pathogens.
在体外建立麦芽寡糖孔蛋白（LamB）在肠致病性大肠杆菌（EPEC）黏附上皮细胞过程中的作用。
使用三株菌，即野生型（WT）EPEC、麦芽寡糖孔蛋白（LamB）突变体DeltalamB和DH5α，研究它们对培养的HEp-2细胞的黏附情况。与WT EPEC相比，发现突变体DeltalamB在黏附方面存在缺陷。当用克隆的lamB基因进行互补时，DeltalamB的黏附恢复到野生型水平。当非黏附菌株DH5α携带克隆的lamB基因时，它也能黏附到HEp-2细胞上。通过电洗脱从WT EPEC中分离出LamB蛋白，并在兔体内制备抗体。通过蛋白质印迹法分析抗体的特异性。抗LamB抗血清降低了WT EPEC对HEp-2细胞的黏附。将LamB蛋白包被在乳胶珠上，这些珠子能黏附到HEp-2细胞上。抗LamB抗血清可阻止珠子黏附到HEp-2细胞上。多序列比对显示，EPEC LamB的L9环与其他几种相关病原体的LamB的L9环有四个氨基酸不同。
LamB作为EPEC的一种替代或额外的黏附因子。
黏附是EPEC等非侵袭性病原体发病机制的重要组成部分。一种已被发现与毒力因子EspB共表达的假定黏附素，如LamB，可能是控制EPEC及相关病原体的潜在疫苗候选物。
