A new immunomodulator, FR-900483.

Abstract

FR-900483 is a new immunoactive substance produced by a fungus, Nectria lucida F-4490. Concanavalin A-stimulated lymphocyte proliferation, which had been suppressed by addition of immunosuppressive factor, was restored to a normal level by the addition of FR-900483. Furthermore, FR-900483 restored the capacity of immunosuppressed mice to produce antibody against sheep red blood cells.