title: Targeting pathogenic postischemic self-recognition by natural IgM to protect against posttransplantation cardiac reperfusion injury.
abstract: BACKGROUND
  Natural IgM antibodies represent a class of innate pattern recognition receptors that recognize danger-associated molecular patterns expressed on stressed or dying cells. They play important roles in tissue homeostasis by disposing of prenecrotic cells and suppressing inflammation. However, ischemic insult leads to a pathogenic level of IgM binding and complement activation, resulting in inflammation and injury. We investigate the role of self-reactive IgM in the unique setting of transplantation where the donor organ undergoes both cold and warm ischemia and global ischemic insult.
  
  
  RESULTS
  By transplanting hearts from wild-type donor mice into antibody-deficient mice reconstituted with specific self-reactive IgM monoclonal antibodies, we identified neoepitopes expressed after transplantation and demonstrated a key role for IgM recognition of these epitopes in graft injury. With this information, we developed and characterized a therapeutic strategy that exploited the postischemia recognition system of natural antibodies. On the basis of neoepitope identification, we constructed an anti-annexin IV single-chain antibody (scFv) and an scFv linked to Crry, an inhibitor of C3 activation (scFv-Crry). In an allograft transplantation model in which recipients contain a full natural antibody repertoire, both constructs blocked graft IgM binding and complement activation and significantly reduced graft inflammation and injury. Furthermore, scFv-Crry specifically targeted to the transplanted heart and, unlike complement deficiency, did not affect immunity to infection, an important consideration for immunosuppressed transplant recipients.
  
  
  CONCLUSIONS
  We identified pathophysiologically important epitopes expressed within the heart after transplantation and described a novel translatable strategy for targeted complement inhibition that has several advantages over currently available approaches.
authors.affiliation: From Department of Microbiology and Immunology, Medical University of South Carolina, Charleston (CA., F.Q., X.Y., P.Z., N.R., S.T.); Department of Medicine and Immunology, University of Colorado Denver, Aurora (L.K., V.M.H.); Department of Pathology, Papworth Hospital, Cambridgeshire, UK (M.G.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC (S.T.).
authors.forename: Carl
authors.initials: C
authors.lastname: Atkinson
authors.affiliation: From Department of Microbiology and Immunology, Medical University of South Carolina, Charleston (CA., F.Q., X.Y., P.Z., N.R., S.T.); Department of Medicine and Immunology, University of Colorado Denver, Aurora (L.K., V.M.H.); Department of Pathology, Papworth Hospital, Cambridgeshire, UK (M.G.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC (S.T.).
authors.forename: Fei
authors.initials: F
authors.lastname: Qiao
authors.affiliation: From Department of Microbiology and Immunology, Medical University of South Carolina, Charleston (CA., F.Q., X.Y., P.Z., N.R., S.T.); Department of Medicine and Immunology, University of Colorado Denver, Aurora (L.K., V.M.H.); Department of Pathology, Papworth Hospital, Cambridgeshire, UK (M.G.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC (S.T.).
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Yang
authors.affiliation: From Department of Microbiology and Immunology, Medical University of South Carolina, Charleston (CA., F.Q., X.Y., P.Z., N.R., S.T.); Department of Medicine and Immunology, University of Colorado Denver, Aurora (L.K., V.M.H.); Department of Pathology, Papworth Hospital, Cambridgeshire, UK (M.G.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC (S.T.).
authors.forename: Peng
authors.initials: P
authors.lastname: Zhu
authors.affiliation: From Department of Microbiology and Immunology, Medical University of South Carolina, Charleston (CA., F.Q., X.Y., P.Z., N.R., S.T.); Department of Medicine and Immunology, University of Colorado Denver, Aurora (L.K., V.M.H.); Department of Pathology, Papworth Hospital, Cambridgeshire, UK (M.G.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC (S.T.).
authors.forename: Nicholas
authors.initials: N
authors.lastname: Reaves
authors.affiliation: From Department of Microbiology and Immunology, Medical University of South Carolina, Charleston (CA., F.Q., X.Y., P.Z., N.R., S.T.); Department of Medicine and Immunology, University of Colorado Denver, Aurora (L.K., V.M.H.); Department of Pathology, Papworth Hospital, Cambridgeshire, UK (M.G.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC (S.T.).
authors.forename: Liudmila
authors.initials: L
authors.lastname: Kulik
authors.affiliation: From Department of Microbiology and Immunology, Medical University of South Carolina, Charleston (CA., F.Q., X.Y., P.Z., N.R., S.T.); Department of Medicine and Immunology, University of Colorado Denver, Aurora (L.K., V.M.H.); Department of Pathology, Papworth Hospital, Cambridgeshire, UK (M.G.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC (S.T.).
authors.forename: Martin
authors.initials: M
authors.lastname: Goddard
authors.affiliation: From Department of Microbiology and Immunology, Medical University of South Carolina, Charleston (CA., F.Q., X.Y., P.Z., N.R., S.T.); Department of Medicine and Immunology, University of Colorado Denver, Aurora (L.K., V.M.H.); Department of Pathology, Papworth Hospital, Cambridgeshire, UK (M.G.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC (S.T.).
authors.forename: V Michael
authors.initials: VM
authors.lastname: Holers
authors.affiliation: From Department of Microbiology and Immunology, Medical University of South Carolina, Charleston (CA., F.Q., X.Y., P.Z., N.R., S.T.); Department of Medicine and Immunology, University of Colorado Denver, Aurora (L.K., V.M.H.); Department of Pathology, Papworth Hospital, Cambridgeshire, UK (M.G.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC (S.T.). tomlinss@musc.edu.
authors.forename: Stephen
authors.initials: S
authors.lastname: Tomlinson
mesh_terms: D000818:Animals; D017314:Annexin A4 / Q000276:immunology; D018033:Antibodies, Bispecific / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use*; D000911:Antibodies, Monoclonal / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use*; D003167:Complement Activation; D000939:Epitopes / Q000276:immunology; D005813:Genes, Synthetic; D016027:Heart Transplantation / Q000009:adverse effects*; D018398:Homeodomain Proteins / Q000235:genetics; D007075:Immunoglobulin M / Q000172:deficiency / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D015425:Myocardial Reperfusion / Q000009:adverse effects*; D015428:Myocardial Reperfusion Injury / Q000276:immunology / Q000517:prevention & control*; D009206:Myocardium / Q000276:immunology; D009928:Organ Specificity; D010743:Phospholipids / Q000276:immunology; D011951:Receptors, Complement / Q000235:genetics / Q000627:therapeutic use*; D017463:Receptors, Complement 3b; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use; D017634:Self Tolerance / Q000276:immunology*; D057127:Single-Chain Antibodies / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use*; D023001:Transplantation Tolerance
chemical_list: D017314:Annexin A4; D018033:Antibodies, Bispecific; D000911:Antibodies, Monoclonal; C081470:Cr1l protein, mouse; D000939:Epitopes; D018398:Homeodomain Proteins; D007075:Immunoglobulin M; D010743:Phospholipids; D011951:Receptors, Complement; D017463:Receptors, Complement 3b; D011993:Recombinant Fusion Proteins; D057127:Single-Chain Antibodies; C064658:RAG-1 protein
keywords: antibodies; complement system proteins; inflammation; ischemia; transplantation
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