ANALYSIS OF THE IMMUNE-RESPONSE TO YERSINIA-ENTEROCOLITICA SEROTYPE-O-9-RELEASED PROTEINS BY IMMUNOBLOT AND ELISA

The immune response towards the released Yersinia enterocolitica outer membrane proteins (Yop) was analysed by immunoblotting and ELISA usin g a rabbit experimental model. Rabbits orogastrically or intravenously infected with the virulent (plasmid-bearing) Y. enterocolitica 0:9 W8 36 strain developed a significant response by (IgG) antibodies to the released proteins having molecular weights of 51 (YopH) and 41 (LcrV) kDa, respectively. However, only in animals infected via the orogastri c: route were specific antibodies of the IgG class found against plasm id-encoded polypeptides of 35 (YopN) and 20 (YopQ) kDa. These results suggest that the expression of Yop in vivo may be conditioned by the r oute of infection used. Using ELISA, a significant response by IgG-cla ss antibodies to YopH protein was evident in the sera from rabbits bot h orogastrically and intravenously infected with the virulent (pYV(+)) Y. enterocolitica 0:9 W836 strain. By contrast, no specific antibodie s to this antigen were detected in sera of rabbit infected with an avi rulent (plasmid-cured) derivative (pYV(-)) strain. Accordingly, this p rotein could be very useful as an antigen in ELISA for serological dia gnosis of infections caused by enteropathogenic strains of Yersinia sp p.