Toxicity of microbial products in cell culture.

Cytotoxicity of a mixed pyrogen preparation and its components as well as native and radiodetoxified lipopolysacharides (LPS) was determined with established HEp-2 cell cultures and by measuring plating efficiency. This proved to be more sensitive to the damaging effect of both microbe-containing LPS (Escherichia coli) and purified LPS. Microorganisms without this compound (Lactobacillus casei, Streptococcus faecalis) seem to be more infifferent on cells, even Saccharomyces cerevisiae has a marked augmenting effect on cell plating. Divergence in null-toxicity between the established cultures and plating efficiency makes it possible to presume that the primary effect of microorganisms on epithelial cells is medited by LPS, and the subsequent liberation of lysosomal proteinases is responsible for major biological effects.