title: Relationship between IL-2 and human T cell colony formation.
abstract: We have tested the reliability of a standard IL-2 microassay (3H-thymidine uptake by IL-2-dependent T cell lines) as a measure of the colony promoting activity (CPA) required for PHA-induced T cell colony growth in semi-solid cultures. Colonies were obtained from freshly isolated mononuclear cells (PBL) (primary colonies) or pooled cells of primary colony (secondary colonies). PHA-stimulated PBL generated primary colonies in the absence of exogenous CPA which, however, when added to the cultures enhanced colony growth. In contrast, primary colonies failed to form PHA-induced secondary colonies in the absence of exogenously supplied CPA. There was a close correlation between the colony forming capacity of PBL and primary colonies from the same donors plated in the presence of added CPA (r = 0.98). When CPA was measured in the secondary colony growth assay and the data compared to IL-2 measurement in the standard IL-2 microassay, CPA and IL-2 levels did not correlate, suggesting that IL-2 and CPA may represent distinct factors. The usefulness of primary colonies as target cells for the measurement of CPA levels in a variety of conditioned media is discussed.
mesh_terms: D002455:Cell Division; D002460:Cell Line; D002478:Cells, Cultured; D002999:Clone Cells / Q000166:cytology; D006133:Growth Substances / Q000032:analysis* / Q000494:pharmacology; D006801:Humans; D007376:Interleukin-2 / Q000032:analysis*; D008213:Lymphocyte Activation; D009930:Organic Chemicals; D010835:Phytohemagglutinins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000145:classification / Q000166:cytology* / Q000276:immunology
chemical_list: D006133:Growth Substances; D007376:Interleukin-2; D009930:Organic Chemicals; D010835:Phytohemagglutinins; C042320:colony promoting activity