title: Mouse B- and T-cell colony formation in vitro. I. Separation of colony-promoting and -inhibiting activities in concanavalin A rat spleen conditioned medium.
abstract: Rat spleen cell cultures exposed for 24 h to concanavalin A (Con A-CM) contain, in addition to interleukin 2 (IL-2), factors that promote colony formation in vitro by mouse T cells (TCPA) and B cells (BCPA). TCPA and BCPA are separable on a Sephadex G-75 column. TCPA has a molecular weight of 15,000 daltons and shows the same elution profile as IL-2. Absorption studies with Con A-activated T cells suggested that TCPA and IL-2 are the same entity. BCPA has an apparent molecular weight of 45,000 daltons and stimulates colony formation by B lymphocytes seeded at very low cell density (10(4) - 5 X 10(4) cells/ml). In contrast to TCPA, BCPA can only be demonstrated in gel-filtered material owing to the presence of B colony suppressor activities in crude Con A-CM. Two B colony inhibitory activities were demonstrated by AcA 34 chromatography of crude Con A-CM with molecular weights of 80,000-130,000 and about 50,000, respectively. Because of the specificity, simplicity and sensitivity of B and T colony formation these assay systems should be valuable tools for in vitro testing of biological activities regulating the immune system.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D002455:Cell Division; D002850:Chromatography, Gel; D003115:Colony-Stimulating Factors / Q000032:analysis*; D003208:Concanavalin A; D003470:Culture Media; D051379:Mice; D051381:Rats; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D003115:Colony-Stimulating Factors; D003470:Culture Media; D003208:Concanavalin A