title: Regulation of antigen-induced human T-lymphocyte responses by calcineurin antagonists.
abstract: BACKGROUND
  Cyclosporin A (CS) and tacrolimus (FK506, FK) are calcineurin antagonists used widely as T-cell immunosuppressants; however, their relative efficacy on antigen-stimulated T-cell subsets remains undefined.
  
  
  OBJECTIVE
  We have examined the effects of CS and FK on antigen-driven proliferation and cytokine generation from human PBMCs and T-cell clones.
  
  
  METHODS
  Proliferation was assessed by tritiated thymidine incorporation. Cytokine generation was assessed by reverse transcription-PCR and ELISA.
  
  
  RESULTS
  Ragweed- and tetanus toxoid-driven proliferation of PBMCs was down-regulated equally by CS or FK. Gene expression for proinflammatory cytokines (IL-4, IL-5, IL-13, and IFN-gamma) assessed by reverse transcription-PCR was down-regulated in a concentration-dependent manner by either drug. Antigen-induced proliferation of ragweed-specific Th0, Th1, or Th2 clones was inhibited by either CS or FK. Cytokine gene expression and protein secretion into culture supernatants (IL-4, IL-5, IL-13, and IFN-gamma) were down-regulated in a concentration-dependent manner by either CS or FK in all relevant T-cell subsets. Interestingly, down-regulation of IL-5 protein generation from Th0 and Th2 clones was consistently less sensitive to either drug than was the effect on either IL-4 or IL-13 protein generation.
  
  
  CONCLUSIONS
  CS and FK promote equivalent down-regulation of Th0, Th1, and Th2 responses; however, IL-5 generation is relatively insensitive to the immunomodulatory effects of calcineurin antagonists.
authors.affiliation: Division of Clinical Immunology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: S E
authors.initials: SE
authors.lastname: Pacocha
authors.forename: A
authors.initials: A
authors.lastname: Oriente
authors.forename: S K
authors.initials: SK
authors.lastname: Huang
authors.forename: D M
authors.initials: DM
authors.lastname: Essayan
mesh_terms: D065095:Calcineurin Inhibitors; D016572:Cyclosporine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology; D007371:Interferon-gamma / Q000378:metabolism; D007378:Interleukins / Q000378:metabolism; D008213:Lymphocyte Activation / Q000187:drug effects*; D015398:Signal Transduction / Q000187:drug effects; D006377:T-Lymphocytes, Helper-Inducer / Q000187:drug effects*; D016559:Tacrolimus / Q000494:pharmacology*
chemical_list: D065095:Calcineurin Inhibitors; D007378:Interleukins; D007371:Interferon-gamma; D016572:Cyclosporine; D016559:Tacrolimus