Infection of HeLa cells with Salmonella typhimurium 395 MS and MR10 bacteria

Abstract

After interaction with HeLa cells cultured in vitro, the fraction of adhering extracellular and that of internalized smooth Salmonella typhimurium 395 MS and rough 395 MR10 have been determined by two different techniques. (i) By using the indirect fluorescent-antibody technique on unfixed and acetone-fixed HeLa cell preparations, intracellular bacteria were considered to become stained only after acetone fixation. (ii) Based on the assumption that gentamicin affects only extracellular bacteria, disintegration of the infected HeLa cells and viable count allowed the determination of internalized bacteria. Both techniques showed that MS as well as MR10 bacteria gained intracellular access, the fraction of MR10 cells doing so being much greater. The net increase in the intracellular bacterial population was small within 3 h of incubation.

Cell‐Surface Properties of Enterotoxigenic and Cytotoxic Salmonella enteritidis and Salmonella typhimurium: Studies on Hemagglutination, Cell‐Surface Hydrophobicity, Attachment to Human Intestinal Cells and Fibronectin‐Binding

“…Attachment of bacteria to mucous membranes of alimentary (16), urinogenital (36), and respiratory tracts, is believed to be mediated by cell surface adhesins of the respective pathogens and receptors on the host cell-surface (4). Reports on in vitro attachment of S. typhimurium strains and LPS-deficient mutants, to macrophages (14), granulocytes (34) and HeLa cells (17,19,20) have shown that the LPSdeficient variants have higher affinity for the cells. Furthermore, expression of cell-surface hydrophobicity and negative charge seem to enhance the interaction of S. typhimurium with these cells.…”

Double immunofluorescence microscopic technique for accurate differentiation of extracellularly and intracellularly located bacteria in cell culture

“…With conventional bright field light microscopy it is impossible to distinguish accurately intracellularly located from extracellularly attached bacteria. To overcome this obstacle, several indirect methods have been developed, e.g., antibiotic treatment to eliminate extracellular bacteria (13,17), optical sectioning through the cells by light microscopy (13), differential interference contrast microscopy (1, 2), identification of cell-adherent bacteria by immunofluorescence microscopy (4,11), and fluorescence quenching technique (9). However, these methods are not exact, and sometimes they lead to artifacts.…”

Invasiveness of Salmonella typhi Strains in HeLa S3 Monolayer Cells

“…Five years later, Giannella et al (5) noted the ability of S. typhimurium to invade HeLa cells. Since then, several investigators analyzed the invasive potential and morphology of the invasion of S. typhimurium in HeLa cell cultures (7)(8)(9)(10)(11)(12). As the first step in our attempt to clarify the invasive potential of S. typhi, HeLa cell monolayers were challenged with eleven S. typhi strains from different sources.…”