Lymphokine-induced IgM secretion by clones of neoplastic B cells

Abstract

The induction of antibody secretion by B cells requires T-cell-derived factors^1–5. Such factors have been described^1,2,6–12 but the precise relationship among these various factors is not clear, and it has been difficult to demonstrate that these factors act directly on the B cell and do not exert their effect via T cells or macrophages. In this report we describe the direct induction of IgM synthesis and secretion in cloned lines of long-term tissue culture adapted neoplastic B cells (BCL₁) by T-cell super-natants from phorbol-12-myristate 13-acetate (PMA)-induced EL-4 cells or concanavalin A (Con A)-induced 7.1.1a cells^5,9. We have termed this activity BCDFμ (B-cell differentiation factor for IgM). The supernatants containing BCDFμ induce activated and neoplastic B cells to secrete IgM⁵ and the factor responsible is distinct from BCGF¹³, interleukin-2 (IL-2)⁵, the classical T-cell replacing factor (TRF) described by Schimpl and Wecker⁵, and immune interferem (IFNγ)⁵.