Immunochemical localization of the fraction-1 antigen, a virulence determinant of Yersinia pestis

ABSTRACT

The distribution of Yersina pestis Fraction-1 (F1) antigen was analyzed in cells grown at 28§C and 37§C. Fractionation of Y. pestis cells followed by analysis in SDS-polyacrylamide gel electrophoresis indicated that the mature form of the F1 antigen is localized in the extracellular matrix and in the cytoplasm. Localization of the F1 antigen was confirmed by immunoblots and a single peptide with a molecular weight of 17,000 daltons was recognized. Electron microscopy of Y. pestis cells labeled with colloidal gold-conjugated antibodies corroborated the extracellular matrix and cytoplasm dual location of the F1 antigen