The Attachment to, and Invasion of HeLa Cells by Salmonella typhimurium: The Contribution of Mannose-sensitive and Mannoseresistant Haemagglutinating Activities

Abstract

The association of the hemagglutinating activities of S. typhimurium cultures with bacterial adhesion to HeLa cells, and the internalization of the bacteria by HeLa cells, was studied. Adhesion was not inhibited by .alpha.-methyl-D-mannoside (i.e., adhesion was mannose-resistant), and only 4 of the 6 strains tested produced type 1 fimbriae and the associated mannose-sensitive hemagglutinin (MSHA). The other 2 strains belonged to the non-fimbriate FIRN biogroup. Cultures of all 6 strains contained a mannose-resistant hemagglutinating (MRHA) activity when grown at 37.degree. C, but cultures of only 1 fimbriate and 1 non-fimbriate strain did so when grown at 18.degree. C. From the comparison of cultures grown at 18.degree. and 37.degree. C, and of mutant strains with the phenotypes MRHA-negative/MSHA-positive, or MRHA-positive/MSHA-negative, it was concluded that the MRHA activity was responsible for the attachment of salmonellae to HeLa cells. Only bacterial adhesion that was resistant to mannose resulted in the internalization of the bacteria by the HeLa cells.