title: Identification of tissue transglutaminase as a novel molecule involved in human CD8+ T cell transendothelial migration.
abstract: During inflammation, T lymphocytes migrate out of the blood across the vascular endothelium in a multistep process. The receptors mediating T cell adhesion to endothelium are well characterized; however, the molecules involved in T cell transendothelial migration (TEM) subsequent to lymphocyte adhesion to the endothelium are less clear. To identify receptors mediating TEM, mAbs were produced against human blood T cells adhering to IFN-gamma-activated HUVEC in mice and tested for inhibition of lymphocyte TEM across cytokine-activated HUVEC. Most of the mAbs were against beta(1) and beta(2) integrins, but one mAb, 6B9, significantly inhibited T cell TEM across IFN-gamma, TNF-alpha, and IFN-gamma plus TNF-alpha-stimulated HUVEC, and did not react with an integrin. 6B9 mAb did not inhibit T cell adhesion to HUVEC, suggesting that 6B9 blocked a novel pathway in T cell TEM. The 6B9 Ag was 80 kDa on SDS-PAGE, and was expressed by both blood leukocytes and HUVEC. Immunoaffinity purification and mass spectrometry identified this Ag as tissue transglutaminase (tTG), a molecule not known to mediate T cell TEM. Treatment of HUVEC with 6B9 was more effective than treatment of T cells. 6B9 blockade selectively inhibited CD4(-), but not CD4(+), T cell TEM, suggesting a role for tTG in recruitment of CD8(+) T lymphocytes. Thus, 6B9 is a new blocking mAb to human tTG, which demonstrates that tTG may have a novel role in mediating CD8(+) T cell migration across cytokine-activated endothelium and infiltration of tissues during inflammation.
authors.affiliation: Departments of. Pediatrics, Microbiology/Immunology and Pathology, Dalhousie University, and Institute for Marine Biosciences, National Research Council, Halifax, Nova Scotia, Canada.
authors.forename: Karkada
authors.initials: K
authors.lastname: Mohan
authors.forename: Devanand
authors.initials: D
authors.lastname: Pinto
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Issekutz
mesh_terms: D000818:Animals; D019138:Antibodies, Blocking / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology* / Q000201:enzymology*; D002448:Cell Adhesion / Q000276:immunology; D002461:Cell Line, Transformed; D002464:Cell Migration Inhibition; D002478:Cells, Cultured; D018925:Chemokines / Q000494:pharmacology; D002634:Chemotaxis, Leukocyte / Q000276:immunology*; D004730:Endothelium, Vascular / Q000737:chemistry / Q000166:cytology* / Q000201:enzymology* / Q000276:immunology; D019084:Fluorescent Antibody Technique, Indirect; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000276:immunology / Q000502:physiology*; D006801:Humans; D007962:Leukocytes / Q000737:chemistry / Q000276:immunology; D013058:Mass Spectrometry; D051379:Mice; D008807:Mice, Inbred BALB C; D011233:Precipitin Tests; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases / Q000737:chemistry / Q000276:immunology / Q000502:physiology*
chemical_list: D019138:Antibodies, Blocking; D000911:Antibodies, Monoclonal; D018925:Chemokines; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D019204:GTP-Binding Proteins