title: T-lymphocyte progenitors in man: biochemical characterization of a colony promoting activity (CPA) active on immature precursors.
abstract: PHA-stimulated lymphocyte supernatants (P-SUP) containing colony promoting activity (CPA) and interleukin-2 (IL-2) were found to drive T-lymphocyte precursor cells (OKT4-OKT8- blood cells) into colonies of mature T cells in agar. Ammonium sulphate precipitation followed by gel filtration on Sephadex G-75 showed that both IL-2 activity and CPA coeluted in the 21,000 MW fraction. Chromatofocusing on a PBE 94 gel equilibrated between pH 7.4 and 4.2 showed that CPA coeluted with the two main peaks of IL-2 (pI 7.2, pI 6.7). Adsorption of IL-2 activity by more than 97% on different T-cell lines did not completely abolish CPA. These results suggest that other(s) factor(s) with the same biochemical characteristics as IL-2 play a role in the induction of growth and differentiation of immature T-cell precursors.
mesh_terms: D002454:Cell Differentiation; D002850:Chromatography, Gel; D006133:Growth Substances / Q000276:immunology; D006801:Humans; D007376:Interleukin-2 / Q000276:immunology; D007525:Isoelectric Focusing; D008213:Lymphocyte Activation; D008970:Molecular Weight; D009930:Organic Chemicals; D010835:Phytohemagglutinins / Q000494:pharmacology; D013234:Stem Cells / Q000166:cytology / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
chemical_list: D006133:Growth Substances; D007376:Interleukin-2; D009930:Organic Chemicals; D010835:Phytohemagglutinins; C042320:colony promoting activity