CHARACTERIZATION OF SUPPRESSIVE IMMUNOGLOBULIN-BINDING FACTOR (IBF) .1. PRODUCTION OF IBF BY A THETA-POSITIVE LYMPHOMA (L-5178-Y)

Abstract

L-5178-Y, a .theta.-positive, Fc receptor-bearing mouse thymona cell line spontaneously releases IBF upon short-term incubation in vitro. IBF produced by L-5178-Y cells is identical in its biologic activity with IBF produced by Fc receptor positive alloantigen-activated T [thymus-derived] cells. It suppresses the in vitro plaque reponse of mouse spleen cells to sheep erythrocytes by interfering mainly with the late phase of the generation of antibody-forming cells. L-5178-Y thymoma affords a homogeneous source of IBF in sufficient quantities for the study of its biochemical nature and the mechanism by which it iterferes with cells participating in antibody synthesis.