Grant C C, Konkel M E, Cieplak W, Tompkins L S
Department of Microbiology and Immunology, Stanford University Medical Center, California 94305.
Infect Immun. 1993 May;61(5):1764-71. doi: 10.1128/iai.61.5.1764-1771.1993.
Previous studies of Campylobacter jejuni have suggested that flagellin is an adhesin for epithelial cells and that motility is a virulence factor of this bacterium. The role of flagella in the interactions of C. jejuni with nonpolarized and polarized epithelial cells was examined with flagellar mutants. Flagellated, nonmotile (flaA flaB+ Mot-) and nonflagellated, nonmotile (flaA flaB Mot-) mutants of C. jejuni were constructed by in vivo homologous recombination and gene replacement techniques. Both classes of mutants were found to adhere to cells of human epithelial origin (INT 407) equally well; however, on the basis of the percentage of the inoculum internalized, internalization of the flaA flaB Mot- mutants was decreased by factors ranging from approximately 30 to 40 compared with the parent. The flaA flaB+ Mot- mutant was internalized by the INT 407 cells at levels six- to sevenfold higher than the flaA flaB Mot- mutants. Both classes of mutants, unlike the parent, were unable to translocate across polarized Caco-2 monolayers. These results indicate that flagella are not involved in C. jejuni adherence to epithelial cells but that they do play a role in internalization. Furthermore, the results suggest that either the motility of C. jejuni or the product of flaA is essential for the bacterium to cross polarized epithelial cell monolayers.
先前对空肠弯曲菌的研究表明，鞭毛蛋白是上皮细胞的黏附素，且运动性是该细菌的一种毒力因子。利用鞭毛突变体研究了鞭毛在空肠弯曲菌与非极化和极化上皮细胞相互作用中的作用。通过体内同源重组和基因替换技术构建了空肠弯曲菌的有鞭毛、无运动性（flaA flaB+ Mot-）和无鞭毛、无运动性（flaA flaB Mot-）突变体。发现这两类突变体对人上皮来源的细胞（INT 407）的黏附能力相同；然而，根据内化接种物的百分比，与亲本相比，flaA flaB Mot-突变体的内化减少了约30%至40%不等。flaA flaB+ Mot-突变体被INT 407细胞内化的水平比flaA flaB Mot-突变体高6至7倍。与亲本不同，这两类突变体均无法穿过极化Caco-2单层细胞。这些结果表明鞭毛不参与空肠弯曲菌对上皮细胞的黏附，但在其内化过程中发挥作用。此外，结果表明空肠弯曲菌运动性或flaA产物对该细菌穿过极化上皮细胞单层至关重要。
