Isolation and Biological Activity of a Novel Cytokine Modulator, Cytoxazone

In the course of our screening for chemical immunomodulators from microbial metabolites, we found that an actinomycete strain (RK95-31) isolated from a soil sample collected in Fukuyama City, Hiroshima Prefecture, Japan, produced a novel immunosuppressant, cytoxazone (Fig. 1). The strain RK95-31 was identified to be Streptomyces sp. and deposited in the National Institute of Bioscience and Human-Technology, Agency of Industrial Science and Technology, Japan, with the accession No. FERM P-16171.