title: Activation of T lymphocytes for adhesion and cytokine expression by toxin-conjugated anti-CD3 monoclonal antibodies.
abstract: BACKGROUND
  Immunosuppressive drugs that target T cells are useful for prolonging allograft survival. The anti-CD3 immunotoxin FN18-CRM9 has been shown to effectively prolong renal allograft survival in a rhesus monkey model of transplantation. However, immunotoxin-treated monkeys showed increased levels of inflammatory cytokines and produced antibodies to donor proteins. To better understand the role of FN18-CRM9 in the production of cytokines and anti-donor antibodies in the monkey model, we examined whether this immunotoxin elicits functional responses in T cells.
  
  
  METHODS
  Purified normal rhesus monkey T cells (>98% purity) were incubated with immunotoxin FN18-CRM9 or the unconjugated anti-CD3 monoclonal antibodies and then examined for changes in protein tyrosine phosphorylation, adhesion to fibronectin, gene expression, and proliferation in the presence or absence of anti-CD28 monoclonal antibodies (mAb) and interleukin-2.
  
  
  RESULTS
  Immunotoxin treatment of T cells in vitro increased protein tyrosine phosphorylation, cell adhesion to the extracellular matrix, and expression of the inflammatory cytokines interferon-gamma and tumor necrosis factor-alpha. These immunotoxin effects were similar in magnitude to those induced by the unconjugated mAb. In contrast, immunotoxin-induced T cell proliferation was markedly less than that induced by the unconjugated mAb. Interestingly, the mitogenic molecules IL-2 and anti-CD28 mAb did not prevent immunotoxin-induced inhibition of cell proliferation.
  
  
  CONCLUSIONS
  The activation of T cells for protein phosphorylation, adhesion, and cytokine expression strongly suggests that the actions of FN18-CRM9 in vivo are not limited to the inhibition of protein synthesis.
authors.affiliation: Department of Surgery, University of Wisconsin, Madison 53792, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: Hamawy
authors.forename: M
authors.initials: M
authors.lastname: Tsuchida
authors.forename: E R
authors.initials: ER
authors.lastname: Manthei
authors.forename: Y
authors.initials: Y
authors.lastname: Dong
authors.forename: J E
authors.initials: JE
authors.lastname: Fechner
authors.forename: J S
authors.initials: JS
authors.lastname: Knechtle
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D017252:CD3 Complex / Q000276:immunology; D002448:Cell Adhesion / Q000502:physiology; D002455:Cell Division / Q000187:drug effects; D016207:Cytokines / Q000378:metabolism*; D005353:Fibronectins / Q000502:physiology; D000922:Immunotoxins / Q000494:pharmacology; D007371:Interferon-gamma / Q000235:genetics; D007376:Interleukin-2 / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000502:physiology*; D008253:Macaca mulatta; D008297:Male; D010766:Phosphorylation / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
chemical_list: D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D016207:Cytokines; D005353:Fibronectins; D000922:Immunotoxins; D007376:Interleukin-2; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; D011505:Protein-Tyrosine Kinases