[Low molecular weight immunomodulators produced by microorganisms]

Immunomodulatory and antitumor activities of the low molecular weight, microbially-derived immunomodulators, bestatin and forphenicinol are reviewed. In addition, the inhibitory effects of the antitumor antibiotics, aclacinomycin and oxanosine, on the generation of suppressor cells are also represented. It is suggested that these substances will be useful for cancer treatment by chemotherapy and/or immunotherapy.