A SALMONELLA-ENTERITIDIS 11RX PILIN INDUCES STRONG T-LYMPHOCYTE RESPONSES

Our previous work, using proteins fractionated by sodium dodecyl sulfa te-polyacrylamide gel electrophoresis to define antigens of Salmonella enteritidis 11RX able to stimulate T cells from S. enteritidis 11RX-p rimed (BALB/c x C57BL/6)F-1 mice, had indicated the presence of a majo r antigenic determinant of 14 to 18 kDa (K.-M. Vordermeier and I. Kotl arski, Immunol. Cell. Biol. 68:299-305, 1990). The 14-kDa size is simi lar to that of the monomeric units of one of the fimbrial structures, SEF14, produced by a human enteropathogen, S. enteritidis 27655 (J. Fe utrier, W. W. Kay, and T. J. Trust, J. Bacteriol. 168:221-227, 1986). Here we present data which indicate that S. enteritidis 11RX also prod uces this protein and that it is able to elicit delayed-type hypersens itivity reactions in S. enteritidis 11RX-primed animals and to stimula te in vitro proliferation of, and cytokine release from, T cells obtai ned from these animals, implying that this fimbrial protein is likely to be an important immunogen of S. enteritidis. The protein was purifi ed to homogeneity and is free from contamination with lipopolysacchari de. Standard immunoblot analysis with unabsorbed S. enteritidis 11RX a ntiserum and antiserum absorbed with Salmonella typhimurium C5 and var ious strains of Escherichia coli, as well as a panel of anti-14-kDa-pr otein monoclonal antibodies, suggests that this fimbrial protein is no t the common antigen expressed by a number of organisms belonging to t he family Enterobacteriaceae. Immunogold electron microscopy with one of these monoclonal antibodies confirms that the 14-kDa protein and SE F14 are identical.