The suppression of inflammatory macrophage-mediated cytotoxicity and proinflammatory cytokine production by transgenic expression of HLA-E

• Published in: Transplant immunology Vol. 29; no. 1; pp. 76 - 81
• Main Authors: Maeda, Akira, Kawamura, Takuji, Ueno, Takehisa, Usui, Noriaki, Eguchi, Hiroshi, Miyagawa, Shuji
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.2013
• Subjects: Allergy and Immunology; Animals; CD47 Antigen - genetics; CD47 Antigen - immunology; CD47 Antigen - metabolism; Cell Line; Cytokines - biosynthesis; Cytokines - genetics; Cytokines - immunology; Endothelial Cells - immunology; Endothelial Cells - metabolism; Endothelial Cells - pathology; Gene Expression; Heterografts; Histocompatibility Antigens Class I - biosynthesis; Histocompatibility Antigens Class I - genetics; Histocompatibility Antigens Class I - immunology; HLA-E; HLA-E Antigens; Humans; Immunoreceptor tyrosine-based inhibition motif (ITIM); Inflammation; Inflammation Mediators - immunology; Inflammation Mediators - metabolism; Inflammatory macrophage; Macrophages - immunology; Macrophages - metabolism; Macrophages - pathology; Organ Transplantation; Pro-inflammatory cytokine; Swine; Transgenes; Transplantation Tolerance; Xenocytotoxicity; Pro-inflammatory cytokine; Inflammatory macrophage; Xenocytotoxicity; Immunoreceptor tyrosine-based inhibition motif (ITIM); HLA-E
• ISSN: 0966-3274; 1878-5492
• DOI: 10.1016/j.trim.2013.08.001

Abstract Background Macrophages participate in xenogenic rejection and represent a major biological obstacle to successful xenotransplantation. The signal inhibitory regulatory protein α (SIRPα) receptor was reported to be a negative regulator of macrophage phagocytic activity via interaction with CD47, its ligand. Because a majority of human macrophages express the inhibitory receptor CD94/NKG2A, which binds specifically to the human leukocyte antigen (HLA)-E and contains immunoreceptor tyrosine-based inhibition motifs (ITIMs), the inhibitory function of HLA class I molecules, HLA-E, on macrophage-mediated cytolysis was examined. The suppressive effect against proinflammatory cytokine production by macrophages was also examined. Methods Complementary DNA (cDNA) of HLA-E, and CD47 were prepared and transfected into swine endothelial cells (SEC). The expression of the modified genes was evaluated by flow cytometry and macrophage-mediated cytolysis was assessed using in vitro generated macrophages. Results Transgenic expression of HLA-E significantly suppressed the macrophage-mediated cytotoxicity. HLA-E transgenic expression demonstrated a significant suppression equivalent to CD47 transgenic expression. Furthermore, transgenic HLA-E suppressed the production of pro-inflammatory cytokines by inflammatory macrophages. Conclusions These results indicate that generating transgenic HLA-E pigs might protect porcine grafts from, not only NK cytotoxicity, but also macrophage-mediated cytotoxicity.