IMMUNOBLOTTING OF YERSINIA PLASMID-ENCODED RELEASED PROTEINS - A TOOLFOR SERODIAGNOSIS

The plasmid-encoded, released proteins (RPs) of Yersinia enterocolitic a serotypes 09 and 03 were separated by sodium dodecyl sulfate (SDS)-p ore gradient gel electrophoresis. The RP-patterns of both serotypes pr oved to be identical. Five major proteins of M(r) 27000, 34700, 35600, 45800, and 46800 were detected. Spontaneously plasmid-cured derivativ es of the two serotypes lost the feature of protein release. By immuno blotting of RP with sera from patients suffering from acute Yersinia i nfections, specific and reproducible band patterns were obtained. Lase r scan densitometry was applied to record the immunoreactions quantita tively. Predominant bands were detected at an M(r) of 34700 and 35600. IgA and IgM antibodies appeared as acute-phase markers rapidly decrea sing in the reconvalescent phase. In contrast, immunoblots of patients with supposed chronic yersiniosis were characterized by a persisting IgA and elevated IgG reactivity. The application of RP as diagnostic a ntigens proved to be advantageous because they are naturally separated from cross-reacting proteins, common to pathogenic and nonpathogenic strains of Yersinia enterocolitica and Y pseudotuberculosis.