Action of Diphtheria Toxin on Cells Cultivated in vitro.

Abstract

Several mammalian cell lines which can be cultivated in vitro are susceptible to low levels of diphtheria toxin. Primary rabbit or monkey kidney cells are the most sensitive and are destroyed by concentration as low as 10-5 flocculating units (Lf)/ml. Toxoid at doses as high as 20 Lf per ml are without effect. Specific antiserum neutralizes the toxin to titer. Rabbit kidney monolayers, then, provide a test system for diphtheria toxin assay as sensitive within a factor 5-10 as the rabbit intradermal test. Other established cell lines,e.g. HeLa and HEP No. 2 (both epithelial carcinoma cells), are sensitive to doses 10 times as high as rabbit kidney. Several lines tested, e.g. "altered" monkey kidney of Parker, were insensitive to doses as high as 1 Lf/ml.