Synthesis of Macrophage Migration Inhibition Factor (MIF) by Immunoglobulin-Producing Lymphocyte Lines and Their Clones

Studies have established the existence of two distinct populations of immunocompetent cells (1). One of these is thymus dependent (TL) and is responsible for cell-mediated immunity. Cells from this population do not contain intracellular immunoglobulin (Ig) and when stimulated in vitro by antigen these cells release substances which have been described as possible effector molecules of cellular immunity (2–7). The second population consists of cells (BL) capable of producing Ig and specific antibody. Numerous human lymphocyte cell lines (LCL), derived from peripheral blood, have now been established in various laboratories, and many of the LCL are known to synthesize Ig (8, 9) as well as some of the putative effector molecules of cell-mediated immunity (10, 11). We have developed clonal sublines of established human LCL to test the hypothesis that production of the effector molecules of cell-mediated immunity occurs in a population of cells distinct from those capable of Ig synthesis.