title: Functional expression of Fas and Fas ligand on human colonic intraepithelial T lymphocytes.
abstract: The expression of Fas, a cell surface receptor directly responsible for triggering cell death by apoptosis, and its ligand (FasL) was investigated on both human colonic intraepithelial T lymphocytes (IELs) and peripheral blood mononuclear lymphocytes (PBMLs). FACS analysis indicated that IELs have increased expression of Fas compared with PBMLs, together with the progress activation marker, CD45RO. A discrete fraction of freshly isolated IELs also constitutively expressed FasL, perhaps as a result of recent in vivo activation. Using monoclonal antibody APO2.7, which detects mitochondrial 7A6 antigen specifically expressed by cells undergoing apoptosis, we further investigated the apoptosis-inducing effect of anti-Fas monoclonal antibody (CH11) on both IELs and PBMLs. FACS analysis revealed that CH11 increased the percentage of apoptotic cells, in IELs but not in PBMLs. Culture with anti-FasL monoclonal antibody (4H9) significantly recovered cell viability in IELs, but not in PBMLs. These results indicate that IELs constitutively express both Fas and FasL and that Fas crosslinking generates signals resulting in apoptosis, outlining a potential mechanism involved in intestinal tolerance.
authors.affiliation: First Department of Surgery, Okayama University Medical School, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Hongo
authors.forename: Y
authors.initials: Y
authors.lastname: Morimoto
authors.forename: H
authors.initials: H
authors.lastname: Iwagaki
authors.forename: K
authors.initials: K
authors.lastname: Kobashi
authors.forename: M
authors.initials: M
authors.lastname: Yoshii
authors.forename: N
authors.initials: N
authors.lastname: Urushihara
authors.forename: A
authors.initials: A
authors.lastname: Hizuta
authors.forename: N
authors.initials: N
authors.lastname: Tanaka
mesh_terms: D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000276:immunology; D017209:Apoptosis; D002470:Cell Survival; D003106:Colon / Q000378:metabolism* / Q000473:pathology; D053222:Fas Ligand Protein; D006801:Humans; D016130:Immunophenotyping; D007413:Intestinal Mucosa; D017493:Leukocyte Common Antigens / Q000096:biosynthesis; D008562:Membrane Glycoproteins / Q000096:biosynthesis*; D008875:Middle Aged; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D019014:fas Receptor / Q000096:biosynthesis*
chemical_list: D000911:Antibodies, Monoclonal; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D019014:fas Receptor; D017493:Leukocyte Common Antigens