title: Characterization of pig intercellular adhesion molecule-2 and its interaction with human LFA-1.
abstract: Understanding molecular interactions between human leukocytes and porcine endothelium is important for the future success of pig-to-human xenotransplantation. Here we describe the analysis of pig intercellular adhesion molecule-2 (ICAM-2). A 1020-basepair ICAM-2 cDNA generated from pig lung RNA contained an open reading frame (ORF) encoding a 277-amino-acid protein with six potential N-linked glycosylation sites. The mature protein sequence was 55% identical to human ICAM-2, with conservation of five out of six residues critical for binding of the human protein to its ligand LFA-1. Northern blot analysis identified ICAM-2 transcripts of 4.0 and 1.4 kb in cultured pig endothelial cells and mRNA was detected in pig lung, spleen, kidney, liver and heart by RT-PCR. The gene structure and endothelial expression of pig ICAM-2 were strikingly similar to those of its human and mouse counterparts. However, unlike human ICAM-2, expression of pig ICAM-2 on cultured endothelial cells was not down-regulated by treatment with the inflammatory cytokines TNF-alpha and IL-1beta. Pig ICAM-2 expressed on stable transfectants supported firm adhesion of cells expressing human LFA-1. This conservation of function across the species barrier suggests that pig ICAM-2 plays a role in the cellular interactions associated with xenograft rejection.
authors.affiliation: Immunology Research Centre, University of Melbourne, St Vincent's Health, Fitzroy 3065, Victoria, Australia.
authors.forename: James W
authors.initials: JW
authors.lastname: Godwin
authors.forename: Anthony J F
authors.initials: AJ
authors.lastname: d'Apice
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Cowan
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000737:chemistry*; D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D019556:COS Cells; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000737:chemistry*; D002460:Cell Line; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D015536:Down-Regulation; D004730:Endothelium, Vascular / Q000166:cytology; D005434:Flow Cytometry; D006084:Graft Rejection; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism; D020014:K562 Cells; D008168:Lung / Q000378:metabolism; D016169:Lymphocyte Function-Associated Antigen-1 / Q000737:chemistry*; D051379:Mice; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D016366:Open Reading Frames; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013552:Swine; D014018:Tissue Distribution; D014158:Transcription, Genetic; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D015703:Antigens, CD; D015815:Cell Adhesion Molecules; D018076:DNA, Complementary; C065289:ICAM2 protein, human; D007375:Interleukin-1; D016169:Lymphocyte Function-Associated Antigen-1; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha