title: The effects of fractions (chalones) obtained from lymphoid organs on lymphocyte proliferation in vitro.
abstract: Aqueous extracts of lymphoid organs were prepared and fractionated by means of gel filtration, ion exchange chromatography, and isoelectric focusing. A protein-containing fraction with a molecular weight of approximately 80,000--90,000 and isoelectric points of 7.6 and 5.3--6.2 was isolated and shown to inhibit reproducibly both thymidine incorporation and proliferation of concanavalin A-stimulated mouse spleen lymphocytes in vitro. This effect appeared specific since proliferation of mastocytoma P-815 and leukemia L-1210 cells remained unaffected. A small molecular weight fraction (500 to 10,000 daltons) was also found to inhibit lymphocyte proliferation in vitro but was without apparent specificity for cell type.
mesh_terms: D000818:Animals; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D005260:Female; D006131:Growth Inhibitors / Q000032:analysis / Q000494:pharmacology*; D066298:In Vitro Techniques; D007525:Isoelectric Focusing; D008214:Lymphocytes / Q000187:drug effects*; D008221:Lymphoid Tissue / Q000502:physiology*; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D008970:Molecular Weight; D013154:Spleen / Q000502:physiology
chemical_list: D006131:Growth Inhibitors