FIMBRIAE AND LECTINOPHAGOCYTOSIS OF SALMO NELLA-TYPHIMURIUM VARIATIO COPENHAGEN (STMVC) - AN ELECTRON-MICROSCOPIC STUDY

On Salmonella Typhimurium variatio copenhagen (STMVC) strains, isolate d from pigeons with acute Salmonellosis, two types of fimbriae can be identified, depending on different growth conditions. In addition to t he common 7nm fimbriae we were able to demonstrate in the electron mic roscope, thin, curled fimbriae 3nm in diameter which are characterized by a mannose-resistant hemagglutination. The simultaneous expression of both types of fimbriae on a single bacterial cell can be induced by transferring a microcolony from agar medium (3 nm fimbriae), to the s urface of a nutrient broth (7 nm fimbriae) and continuing the incubati on. One selected strain expresses only the thin fimbriae on nearly all the bacteria on an agar medium. These thin fimbria seem to play a rol e in the lectinophagocytosis in macrophage cultures. The attachment of Salmonellae mediated by these fimbriae as well as the internalization of fimbriated cells by macrophages is shown in the electron microscop e and discussed in respect to infection and immunization.