Lymphotoxin and interferon production by rosette-separated human peripheral blood leukocytes

Abstract

Experiments were undertaken to investigate the abilities of human T and B lymphocytes to produce the lymphokines interferon (IF) and lymphotoxin (LT). Sheep erythrocyte rosette-forming cells (E-RFC) were separated from nonrosetting cells by sedimentation on Ficoll-Hypaque gradients. Unseparated peripheral blood mononuclear cells and T-cell-enriched and B-cell-enriched populations were assayed for lymphokine production and proliferative response after stimulation with the T-cell mitogen, phytohemagglutinin (PHA), or the B- and T-cell mitogen, staphylococcal phage lysate (SPL). PHA induced LT production and cell proliferation primarily in the E-RFC-enriched population. In contrast, SPL preferentially induced LT production in the E-RFC-depleted population. SPL stimulated cell proliferation and induced equivalent IF production in both populations. Thus, PHA and SPL have differential and contrasting effects in terms of the induction of LT production and cell proliferation in T-cell and B-cell populations. In the same experiments there was no population specificity in induction of IF production. Therefore, the potentials to produce LT and IF appear to be inherent in both cell populations with their in vitro expression being dependent upon the nature of the stimulus.