title: The unique role of interferon-gamma in the regulation of MHC expression on arterial endothelium.
abstract: We examined the expression of MHC class I and II in the arterial endothelium of interferon-gamma (IFN-gamma, GKO) and IFN-gamma-R (IFN-gamma-R, GRKO) gene knockout mice in comparison with mice with intact IFN-gamma and IFN-gamma-R genes, BALB/c and 129Sv/J wild-type, respectively. The GKO and GRKO were produced by gene targeting. MHC class I and II expression was assessed by mAb binding to frozen tissue (kidney, spleen, heart, liver) sections by immunoperoxidase staining in the basal state and after various stimuli: allogeneic cells, oxazolone skin sensitization, LPS, and rIFN-gamma. As controls, we also examined the expression of two other IFN-gamma inducible genes present in the endothelium, Ly-6 and ICAM-1. We found that basal class I expression was present in the small arteries and arterioles of BALB/c and 129Sv/J wild-type mice but absent from arterial endothelium of GKO and GRKO mice. Class I was induced in the endothelium of BALB/c and 129Sv/J wild-type mice by three in vivo stimuli: allogeneic, LPS, and oxazolone, whereas class II was only induced after allogeneic stimulus. Administration of rIFN-gamma induced class I in the endothelium of GKO and BALB/c wild-type mice. The basal expression of Ly-6 and ICAM-1 was similar in the arteries of GKO and BALB/c wild-type mice, indicating that, the basal expression of these proteins in endothelium is IFN-gamma independent, unlike class I. In summary, basal class I expression in arterial endothelium is not constitutive as previously believed, but is dependent on basal IFN-gamma production. IFN-gamma has an essential role in the induction of class I and II expression in arterial endothelium. The fact that MHC class I is induced in endothelium may be useful therapeutically for reduction of immune recognition in transplantation.
authors.affiliation: Department of Medicine, University of Alberta, Edmonton, Canada.
authors.forename: N
authors.initials: N
authors.lastname: Goes
authors.forename: J
authors.initials: J
authors.lastname: Urmson
authors.forename: M
authors.initials: M
authors.lastname: Hobart
authors.forename: P F
authors.initials: PF
authors.lastname: Halloran
mesh_terms: D000818:Animals; D000950:Antigens, Ly / Q000096:biosynthesis; D001158:Arteries / Q000737:chemistry; D015415:Biomarkers; D004729:Endothelium, Lymphatic / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism; D005786:Gene Expression Regulation; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis; D007371:Interferon-gamma / Q000235:genetics* / Q000494:pharmacology / Q000502:physiology*; D008285:Major Histocompatibility Complex / Q000235:genetics*; D008565:Membrane Proteins / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D011994:Recombinant Proteins
chemical_list: D000950:Antigens, Ly; D015415:Biomarkers; D008565:Membrane Proteins; D011994:Recombinant Proteins; D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma