title: Acid treatment enhances IL-2 activity of conditioned medium.
abstract: Although conditioned medium (CM) from human lymphocytes or mononuclear cells is the most readily available source of interleukin-2 (IL-2) for human T cell culture, its IL-2 activity in our experience is inconsistent. It is likely that this is, at least in part, due to the presence of toxic substances in the CM. Using CM from TPA/SEA induced human mononuclear cells, we have found that acid treatment (pH 2.0, greater than 30 min) significantly improves its ability to promote T cell growth. It is postulated that the selection process which occurs in cultures of mitogen stimulated T cells may result in cells which are sensitive to mitogen-induced lymphotoxins and that these are inactivated by the acid treatment. Since acid treatment did not similarly improve the T cell growth promoting ability of PHA induced, lectin-free commercial IL-2, there must be other differences between it and our CM, which play a role in T cell growth.
mesh_terms: D002470:Cell Survival; D002478:Cells, Cultured; D003470:Culture Media; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007158:Immunologic Techniques; D007376:Interleukin-2 / Q000502:physiology*; D008213:Lymphocyte Activation; D013205:Staphylococcal Protein A / Q000494:pharmacology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D003470:Culture Media; D007376:Interleukin-2; D013205:Staphylococcal Protein A