title: Monocyte produced burst-promoting activity after stimulation with lymphokine.
abstract: Normal monocytes were stimulated by lymphokine(s) from a homogenous population of malignant T cells of the helper phenotype (OKT 3+/4+/6-/8-/11+). The resultant monocyte-conditioned medium after stimulation with T cell-conditioned medium (M-CM+) was assayed for burst-promoting activity. The number of burst-forming units-erythriod (BFU-E) in methylcellulose cultures of normal human nonadherent peripheral blood cells increased by nearly threefold in the presence of 5% M-CM+. This activity was lost after the conditioned medium was boiled for 20 min. The addition of 5% conditioned medium (CM) from unstimulated monocytes did not significantly increase BFU-E proliferation. We conclude that lymphokine(s) from malignant T cells of the helper phenotype stimulate normal monocytes to produce a heat-sensitive monokine that increases BFU-E proliferation.
mesh_terms: D003114:Colony-Forming Units Assay; D003115:Colony-Stimulating Factors / Q000378:metabolism*; D004920:Erythropoiesis / Q000187:drug effects; D006801:Humans; D008222:Lymphokines / Q000494:pharmacology*; D009000:Monocytes / Q000187:drug effects* / Q000378:metabolism
chemical_list: D003115:Colony-Stimulating Factors; D008222:Lymphokines