Introduction of the cell survival gene bcl-xL improves the viability of CTLL-2 cells without affecting their IL-2 proliferative response. Implications for the development of bioassays.
A standard method for the quantitation of cytokines is to perform a bioassay in which aliquots of samples are compared to known concentrations of a cytokine in supporting the proliferation of a cytokine-dependent cell line. In most instances however, these cell lines are dependent on the cytokine not only for proliferation but also for survival. For example, a cell line that is commonly utilized for interleukin-2 (IL-2) bioassays is the IL-2-dependent line, CTLL-2. CTLL-2 cells will die rapidly by apoptosis if withdrawn from IL-2, thus these cells can be difficult to maintain in culture for extended periods. Overexpression of the anti-apoptotic protein Bcl-x(L) can enhance CTLL-2 survival in the absence of IL-2. However, while overexpression of Bcl-x(L) can prevent CTLL-2 cells from dying in the absence of IL-2, overexpression of Bcl-x(L) does not impair the ability of CTLL-2 cells to be used for proliferation-based IL-2 bioassays. Thus the bcl-x(L)-transfected CTLL-2 cells are equivalent to the parental cell line for determination of IL-2 levels in a culture supernatant, yet are easier to maintain in culture. Introduction of Bcl-x(L) or Bcl-2 into other factor-dependent cell lines may also simplify their maintenance without significantly affecting their utility in bioassays.
Boise
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LH
Gwen Knapp Center for Lupus and Immunology Research, University of Chicago, IL 60637, USA.
McShan
C L
CL
Thompson
C B
CB
D000818:Animals; D002455:Cell Division / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D002460:Cell Line; D002470:Cell Survival / Q000235:genetics / Q000276:immunology; D004306:Dose-Response Relationship, Immunologic; D007118:Immunoassay; D007376:Interleukin-2 / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000187:drug effects* / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000494:pharmacology; D019253:Proto-Oncogene Proteins c-bcl-2; D011519:Proto-Oncogenes; D013602:T-Lymphocytes, Cytotoxic / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D051020:bcl-X Protein
D007376:Interleukin-2; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051020:bcl-X Protein