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.
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 humanleukocyte 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-Epigs might protect porcine grafts from, not only NK cytotoxicity, but also macrophage-mediated cytotoxicity.
Authors: Nicholas G Battaglia; Joseph D Murphy; Taylor P Uccello; Angela Hughson; Nicholas W Gavras; Johnathan J Caldon; Scott A Gerber; Edith M Lord Journal: J Immunol Date: 2022-07-15 Impact factor: 5.426
Authors: Zhen Bian; Lei Shi; Ya-Lan Guo; Zhiyuan Lv; Cong Tang; Shuo Niu; Alexandra Tremblay; Mahathi Venkataramani; Courtney Culpepper; Limin Li; Zhen Zhou; Ahmed Mansour; Yongliang Zhang; Andrew Gewirtz; Koby Kidder; Ke Zen; Yuan Liu Journal: Proc Natl Acad Sci U S A Date: 2016-08-30 Impact factor: 11.205