Control of proliferation and differentiation in B lymphocytes by anti-Ig antibodies and a serum-derived cofactor.

Abstract

The effects of various anti-Ig [immunoglobulin] antibodies on different B [bone marrow-derived] lymphocyte functions were investigated. With the proper accessory cofactor(s) derived from serum, anti-Ig M antibodies induced a vigorous proliferative response in normal adult murine B cells, while polyspecific anti-Ig and anti-IgD had no effect. Without the required cofactor, all 3 anti-Ig antibodies were inhibitory for mitogenic responses. All 3 anti-Ig antibodies were also inhibitory for mitogen-induced antibody responses with or without the cofactor. Even with the required cofactor, neonatal B cells as well as adult C3H/HeI B cells were not triggered into proliferation by anti-IgM. Finally, the cofactor required for anti-IgM-triggered mitogenesis was generated from serum by 2-mercaptoethanol and was approximately 65,000 in MW. By lymphocyte surface IgM molecule are involved in triggering and suppression in some responses, depending on the developmental state of the B cell and the presence or absence of accessory influences. IgD gave evidence only of being suppressive.