Determination of mammalian cell (strain HeLa) inhibition by an agar diffusion technic. I. Quantitative assay methods.

Paper chromatography has proved to be a powerful tool in an antibiotic screening program (1). It serves the following purposes: (a) it pro vides an early characterization of the antibiotic activity as new or old, (6) it determines whether single or multiple activities are present, and (c) it predicts the solubility characteristics of the activ ity and probable extraction behavior. Thus, at a very early stage, important information is made available to both the microbiologist and biochem ist which helps to determine interest in the anti biotic and to accelerate the studies leading to its isolation and purification. The search for antitumor agents in such fer mentation materials requires the same basic ap proach as does antibiotic screening. This report will describe one solution to such need: the use of mammalian cell bioautographs of antitumor agents isolated in crude or purified form from fer mentation liquors of actinomycetes and chromatographed on paper strips.