title: Human antibody reactivity against xenogeneic N-glycolylneuraminic acid and galactose-α-1,3-galactose antigen.
abstract: Despite the development of α1,3-galactosyl transferase-knockout (GTKO) pigs, acute humoral xenograft rejection caused by antibodies against non-Gal antigens, along with complement activation, are hurdles that need to be overcome. Among non-Gal antigens, N-glycolylneuraminic acid (Neu5Gc) is considered to play an important role in xenograft rejection in human.
  
  
  
  We generated human embryonic kidney 293 (HEK293) cells that expressed xenogeneic Neu5Gc (HEK293-pCMAH) or α1,3Gal (HEK293-pGT) antigen and investigated the degree of human antibody binding and complement-dependent cytotoxicity (CDC) against these antigens using 100 individual human sera.
  
  
  
  Both IgM and IgG bound to α1,3Gal, while only IgG bound to Neu5Gc. Of the ABO blood groups, the degree of IgG binding to α1,3Gal was highest for blood group A. The degree of CDC against HEK293-pCMAH cells was significantly lower than that against HEK293-pGT cells. However, CDC against HEK293-pCMAH cells was significantly higher than that against control HEK293 cells. In addition, the severity of CDC against HEK293-pCMAH cells positively correlated with that against GTKO pig aortic endothelial cells (PAECs), suggesting that Neu5Gc is the main antigen in GTKO PAECs. Similar to antibody-binding activity, only IgG binding correlated with CDC against HEK293-pCMAH cells. The most common subclass of IgGs against Neu5Gc was IgG1, which typically induces strong complement activation.
  
  
  
  We showed that IgG-mediated CDC was detected in Neu5Gc-overexpressed HEK293 cells incubated with human sera; however, this antibody reactivity to Neu5Gc was highly variable among individuals. Our results suggest that additional modifications to the CMAH gene should be considered for widespread use of pig organs for human transplants.
authors.affiliation: Transplantation Research Institute, Seoul National University College of Medicine, Seoul, Korea.|Graduate School of Translational Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Sunghoon
authors.initials: S
authors.lastname: Hurh
authors.affiliation: Transplantation Research Institute, Seoul National University College of Medicine, Seoul, Korea.|Graduate School of Translational Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Bohae
authors.initials: B
authors.lastname: Kang
authors.affiliation: Department of Pharmaceutical Engineering, College of Life and Health Sciences, Hoseo University, Asan, Chungcheongnam-do, Korea.
authors.forename: Inho
authors.initials: I
authors.lastname: Choi
authors.affiliation: Designed Animal & Transplantation Research Institute, Institute of Green Bio Science & Technology, Seoul National University, Pyeongchang, Gangwon-do, Korea.
authors.forename: Bumrae
authors.initials: B
authors.lastname: Cho
authors.affiliation: Transplantation Research Institute, Seoul National University College of Medicine, Seoul, Korea.|Graduate School of Translational Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Eun Mi
authors.initials: EM
authors.lastname: Lee
authors.affiliation: Transplantation Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Hwajung
authors.identifier: 0000-0001-8470-1514
authors.initials: H
authors.lastname: Kim
authors.affiliation: Designed Animal & Transplantation Research Institute, Institute of Green Bio Science & Technology, Seoul National University, Pyeongchang, Gangwon-do, Korea.
authors.forename: Young June
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Transplantation Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Yun Shin
authors.initials: YS
authors.lastname: Chung
authors.affiliation: Department of Nephrology, Ajou University School of Medicine, Suwon, Gyeonggi-do, Korea.
authors.forename: Jong Cheol
authors.initials: JC
authors.lastname: Jeong
authors.affiliation: Graduate School of Medicine, Korea University, Seoul, Korea.
authors.forename: Jong-Ik
authors.initials: JI
authors.lastname: Hwang
authors.affiliation: Department of Life Science, Gachon University, Seongnam, Korea.
authors.forename: Jae Young
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Designed Animal & Transplantation Research Institute, Institute of Green Bio Science & Technology, Seoul National University, Pyeongchang, Gangwon-do, Korea.|Department of Theriogenology and Biotechnology, College of Veterinary Medicine, Seoul National University, Seoul, Korea.|Research Institute for Veterinary Science, Seoul National University, Seoul, Korea.
authors.forename: Byeong Chun
authors.initials: BC
authors.lastname: Lee
authors.affiliation: Academy of Immunology and Microbiology, Institute for Basic Science, Pohang, Korea.|Department of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang, Korea.|Division of Developmental Immunology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA.
authors.forename: Charles D
authors.initials: CD
authors.lastname: Surh
authors.affiliation: Transplantation Research Institute, Seoul National University College of Medicine, Seoul, Korea.|Transplantation Center, Seoul National University Hospital, Seoul, Korea.
authors.forename: Jaeseok
authors.initials: J
authors.lastname: Yang
authors.affiliation: Transplantation Research Institute, Seoul National University College of Medicine, Seoul, Korea.|Designed Animal & Transplantation Research Institute, Institute of Green Bio Science & Technology, Seoul National University, Pyeongchang, Gangwon-do, Korea.|Transplantation Center, Seoul National University Hospital, Seoul, Korea.|Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Curie
authors.initials: C
authors.lastname: Ahn
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D003167:Complement Activation / Q000276:immunology; D005690:Galactose / Q000276:immunology*; D006084:Graft Rejection / Q000276:immunology*; D057809:HEK293 Cells; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology*; D009438:Neuraminic Acids / Q000276:immunology* / Q000378:metabolism; D013552:Swine; D014183:Transplantation, Heterologous / Q000379:methods
chemical_list: D007074:Immunoglobulin G; D009438:Neuraminic Acids; C032592:N-glycolylneuraminic acid; D005690:Galactose
keywords: Neu5Gc; antibody; antibody isotype; complement activation; xenoantigen