title: Colony growth of T lymphocytes in vitro. Control and regulation of clonal formation.
abstract: Human lymphocytes stimulated with PHA in liquid phase (step 1) and then seeded in a two-layer soft agar system (step 2) grew and developed into T cell colonies. Colony formation was enhanced when the agar culture was supplemented with culture fluid obtained from phytohemagglutin-treated lymphocytes (Ly-CF). Untreated lymphocytes plated directly in the soft agar system also developed into colonies if the culture medium contained Ly-CF. Mitogen-sensitized T lymphocytes produced a lymphocyte colony enhancing factor in the culture fluid which stimulated lymphocytes into colony formation. The best plating efficiency (1:250) was attained when blood mononuclear cells were seeded. When spleen cell culture fluid or a highly concentrated blood-adherent cell population was added to the soft agar, colony development was strongly inhibited. Monocytes-macrophages secrete a lymphocyte colony inhibiting factor in the culture medium. These lymphokines exert a competitive influence on T cells and thus control and regulate clonal proliferation.
mesh_terms: D000362:Agar; D002455:Cell Division; D002999:Clone Cells; D003115:Colony-Stimulating Factors / Q000096:biosynthesis / Q000494:pharmacology; D003584:Cytological Techniques; D006801:Humans; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism; D008222:Lymphokines / Q000494:pharmacology; D010835:Phytohemagglutinins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000166:cytology* / Q000187:drug effects
chemical_list: D003115:Colony-Stimulating Factors; D008222:Lymphokines; D010835:Phytohemagglutinins; D000362:Agar