ROLE OF YADA-MEDIATED COLLAGEN-BINDING IN ARTHRITOGENICITY OF YERSINIA-ENTEROCOLITICA SEROTYPE-O-8 - EXPERIMENTAL STUDIES WITH RATS

Outer membrane protein YadA, Yersinia adhesin, is one of the plasmid-e ncoded virulence factors of yersiniae. YadA protects bacteria against host defense through several different mechanisms. One important role of YadA is to mediate binding to several collagen types. Our recent st udy revealed that a yadA null mutant of Yersinia enterocolitica seroty pe O:8 has a drastically reduced arthritogenic capacity when injected intravenously into Lewis rats. To further characterize the arthritogen ic role of YadA, we repeated the rat experiments with strain Y. entero colitica O:8/pYV082; this strain expresses a YadA deletion derivative lacking 22 amino acids from the amino-terminal hydrophobic region and does not bind to collagen. Y. enterocolitica O:8/pYV082 induced arthri tis in 5 to 14% of rats inoculated with arthritogenic doses, whereas t he arthritis incidence with the wild-type parent strain was 65%. The p arent strain was slightly more virulent than Y. enterocolitica O:8/pYV 082, as determined by rat mortality. It also frequently induced skin a bscesses, whereas Y. enterocolitica O:8/pYV082 did not. Infection kine tics in spleen and mesenteric lymph nodes were about the same with bot h of the bacterial. strains used, and the same was true of the Yersini a-specific antibody response. Altogether, these results suggest that Y adA-mediated collagen binding contributes to the arthritogenicity of Y . enterocolitica O:8.