title: Apoptotic effects of antilymphocyte globulins on human pro-inflammatory CD4+CD28- T-cells.
abstract: BACKGROUND
  Pro-inflammatory, cytotoxic CD4(+)CD28(-) T-cells with known defects in apoptosis have been investigated as markers of premature immuno-senescence in various immune-mediated diseases. In this study we evaluated the influence of polyclonal antilymphocyte globulins (ATG-Fresenius, ATG-F) on CD4(+)CD28(-) T-cells in vivo and in vitro.
  
  
  RESULTS
  Surface and intracellular three colour fluorescence activated cell sorting analyses of peripheral blood mononuclear cells from 16 consecutive transplant recipients and short-term cell lines were performed. In vivo, peripheral levels of CD3(+)CD4(+)CD28(-) T-cells decreased from 3.7 ± 7.1% before to 0 ± 0% six hours after ATG-F application (P = 0.043) in 5 ATG-F treated but not in 11 control patients (2.9 ± 2.9% vs. 3.9 ± 3.0%). In vitro, ATG-F induced apoptosis even in CD4(+)CD28(-) T-cells, which was 4.3-times higher than in CD4(+)CD28(+) T-cells. ATG-F evoked apoptosis was partially reversed by the broad-spectrum caspase inhibitor benzyloxycarbonyl (Cbz)-Val-Ala-Asp(OMe)-fluoromethylketone (zVAD-fmk) and prednisolon-21-hydrogensuccinate. ATG-F triggered CD25 expression and production of pro-inflammatory cytokines, and induced down-regulation of the type 1 chemokine receptors CXCR-3, CCR-5, CX3CR-1 and the central memory adhesion molecule CD62L predominately in CD4(+)CD28(-) T-cells.
  
  
  CONCLUSIONS
  In summary, in vivo depletion of peripheral CD3(+)CD4(+)CD28(-) T-cells by ATG-F in transplant recipients was paralleled in vitro by ATG-F induced apoptosis. CD25 expression and chemokine receptor down-regulation in CD4(+)CD28(-) T-cells only partly explain the underlying mechanism.
authors.affiliation: Department of Internal Medicine, Clinic of Internal Medicine I, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Christina
authors.initials: C
authors.lastname: Duftner
authors.forename: Christian
authors.initials: C
authors.lastname: Dejaco
authors.forename: Paul
authors.initials: P
authors.lastname: Hengster
authors.forename: Klaudija
authors.initials: K
authors.lastname: Bijuklic
authors.forename: Michael
authors.initials: M
authors.lastname: Joannidis
authors.forename: Raimund
authors.initials: R
authors.lastname: Margreiter
authors.forename: Michael
authors.initials: M
authors.lastname: Schirmer
mesh_terms: D000328:Adult; D000961:Antilymphocyte Serum / Q000276:immunology / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000276:immunology; D018106:CD28 Antigens / Q000032:analysis*; D017252:CD3 Complex; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D020169:Caspases / Q000378:metabolism; D016207:Cytokines / Q000096:biosynthesis; D015536:Down-Regulation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D006801:Humans; D007155:Immunologic Factors / Q000276:immunology / Q000494:pharmacology*; D007249:Inflammation / Q000276:immunology; D007376:Interleukin-2 / Q000378:metabolism; D008212:Lymphocyte Depletion; D008297:Male; D008875:Middle Aged; D016377:Organ Transplantation; D019707:Receptors, Chemokine / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D018417:Th1 Cells / Q000187:drug effects / Q000276:immunology; D057705:Transendothelial and Transepithelial Migration / Q000187:drug effects; D055815:Young Adult; D019014:fas Receptor / Q000378:metabolism
chemical_list: D000961:Antilymphocyte Serum; D018106:CD28 Antigens; D017252:CD3 Complex; D016207:Cytokines; D007155:Immunologic Factors; D007376:Interleukin-2; D019707:Receptors, Chemokine; D019014:fas Receptor; D020169:Caspases