PURIFICATION AND CHARACTERIZATION OF YERSINIA-ENTEROCOLITICA ENVELOPEPROTEINS WHICH INDUCE ANTIBODIES THAT REACT WITH HUMAN THYROTROPIN RECEPTOR

Graves' disease is an autoimmune disease mediated by autoantibodies to the thyrotropin receptor (TSHR). Several studies have suggested that the development of Graves' disease may be linked to infection with the enteric pathogen Yersinia enterocolitica. Using the purified recombin ant extracellular domain of human TSHR (ETSHR), we have recently shown that immunization of mice with Y. enterocolitica results in the produ ction of antibodies capable of reacting with the ETSHR. In this study, we identify two low molecular weight (5.5 kDa and 8 kDa) envelope pro teins of Yersinia containing epitopes that are crossreactive with the TSHR. Identification of these crossreactive envelope proteins was achi eved by Western blotting using affinity-purified anti-Y. enterocolitic a antibodies that specifically react with the TSHR and, conversely, fo r envelope proteins of Yersinia. Confirmation that these Yersinia prot eins contained crossreactive epitopes with the ETSHR was obtained by i mmunizing mice with partially purified envelope proteins, which result ed in the production of Abs that recognized the ETSHR. Further, some o f the cross-reactive envelope proteins were purified with SDS-PAGE and HPLC. The crossreactive envelope proteins were shown to be chromosoma lly encoded, exposed on the surface of bacteria, and produced by Virul ent as well as avirulent strains of Yersinia (Y. pestis, Y. pseudotube rculosis, Y. enterocolitica VW+, and Y. enterocolitica VW-). These res ults identify for the first time the Yersinia envelope proteins that a re crossreactive with the ETSHR. Availability of these proteins will a llow future studies to determine whether patients with Graves' disease have a unique immune response against these proteins when compared wi th healthy individuals.