Invasion of HeLa Cells by Salmonella typhimurium: A Model for Study of Invasiveness of Salmonella

Abstract

Microbial invasion of the gastrointestinal mucosa is an essential step in the pathogenesis of enteritis caused by Salmonella typhimurium. To provide a convenient model for assessing strains for invasive potential, we have correlated the ability of strains of S. typhimurium to invade HeLa cells in vitro with their capacity to invade rabbit ileal mucosa in vivo. Strains that invaded HeLa cells also invaded rabbit ileal mucosa, and strains failing to penetrate HeLa cells lacked the capacity to invade rabbit mucosa. No correlation between the murine ld₅₀ value and the capacity in invade either HeLa cells or rabbit mucosa was observed. Furthermore, alterations in cell-wall lipopolysaccharide, while affecting virulence (ld₅₀) for mice, did not appear to influence invasive potential in either model. In addition to being a convenient system for screening strains of S. typhimurium for invasive potential, the HeLa-cell model may prove useful for studying those parameters involved in the process of invasion itself.