Ingestion and survival of Y. pseudotuberculosis in HeLa cells

Abstract

HeLa cells were infected with Yersinia pseudotuberculosis for 0.5-3 h. Intracellular bacteria could then be demonstrated by three different techniques: viable count, fluorescent-antibody staining and electron microscopy. Most of the bacteria seemed to be viable, since there was a good positive correlation (0.94) between viable and fluorescent bacteria. The bacterial uptake seemed to be mediated by a phagocytic-like procedure. The intracellular bacteria seemed to reside in vacuoles some of which increased in size as a function of time. The kinetics of infection was studied after addition of 10(7) or 10(9) bacteria per cell culture (2 X 10(6) cells). After a lag period of about 30 min there was a linear increase of intracellular bacteria, and this uptake proceeded for 1-2 h until most of the bacteria were ingested or an upper limit of ingested bacteria was reached. The upper limit was calculated to be a mean of 60 per infected cell in the cell culture. More than 90% of the cells could be infected and a reasonable number of the bacteria survive in the cells for at least 3 days, as demonstrated by the viable-count technique. The bacteria-cell system may be used to study, for example, the effect of antibiotics or antibodies on intracellular bacteria and pathogenicity of intracellular diseases.

The ability of some Yersinia enterocolitica strains to invade HeLa cells

“…Invasiveness of enteropathogenic Eschericllia coli (1 l), Saltnonella (13), Slligella (12), and Yersinia pseudotuber.culosis (8) in human cell cultures have been reported. In this study, Y .…”

Cloning and molecular characterization of genes whose products allow Salmonella typhimurium to penetrate tissue culture cells.

“…Several investigators have made use of cultured mammalian cells as a model to study bacterial invasiveness (5)(6)(7)(8). Infection of tissue culture monolayers provides a simple in vitro system that mimics the invasion of enterocytes in vivo and in some instances has been correlated with virulence (9).…”

Cultured mammalian cells attach to the invasin protein of Yersinia pseudotuberculosis.

“…Yersinia pseudotuberculosis is a bacterium that is able to enter cultured mammalian cells (5,11). This in vitro property is used as a model for invasive diseases caused by the microorganism.…”