Metabolism of rabbit kidney cells incubated in vitro with phospholipase C from Staphylococcus aureus and Clostridium perfringens

An established cell line of rabbit kidney cells (RK-13) was treated with subcytotoxic concentrations of two highly purified toxic bacterial phospholipases C, beta-toxin from Staphylococcus aureus and alpha-toxin from Clostridium perfringens. Although the concentrations used did not increase the number of cells stained with nigrosin, a decrease in active uptake of ⁸⁶Rb and increase of leakage out of the cell of ⁸⁶Rb was noted within 60 min of incubation at 37°C with 40 hemolytic units of beta-toxin and 10 enzymatic units of alpha-toxin. Binding of ouabain to the cells was also impaired. Cl. perfringens alpha-toxin caused in general much greater damage to the cells than the staphylococcal beta-toxin, which is in accordance with the broader substrate specificity of the former enzyme. Cell metabolism was also studied up to 8 hr after incubation with the toxins for 1 hr. Staphylococcal beta-toxin temporarily inhibited the uptake of ³H-glycine, but not ³H-thymidine or ³H-uridine. Cl. perfringens alpha-toxin, on the other hand, affected first the uptake of ³H-thymidine and later the uptake of ³H-glycine. The intracellular content of cyclic AMP was doubled after 1 hr, but declined in a few hr below the control value. It is concluded that the cytoplasmic membrane was affected by these two enzymatic toxins in subcytotoxic doses, and that the different membrane functions investigated varied as to their dependence upon an intact phospholipid milieu.