title: Analysis of the serine protease function of porcine factor I produced by liver cells for xenotransplantation.
abstract: The use of a bioartificial liver with pig liver cells in the treatment of fulminant hepatic failure has already begun as a clinical trial in several countries. Therefore, studies on plasma complement regulatory proteins of the pig are necessary, because the liver produces them. Complement factor I is a serine protease that cleaves C3b and C4b. The DNA sequences of factor I have been reported in many species, with the noted exception of pigs. In this study, porcine factor I was cloned and an open reading frame of 1794 base pairs were identified. The predicted amino acid sequence maintained a relatively high homology compared to those of other mammals, especially in the serine protease (SP) region. The cell membrane-bound forms of the porcine and the human SP domain of factor I were constructed. Amelioration of complement-mediated cell lysis by these molecules was then tested, using several kinds of sera and Chinese hamster ovary (CHO) cell transfectants. Both molecules had a suppressing effect on pig, human and dog complements, indicating little species-specificity. Further studies of other plasma complement regulatory proteins produced from pig liver cells will need to be considered as the primary feature of the pig bioartificial liver.
authors.affiliation: Division of Organ Transplantation, Department of Molecular Therapeutics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Kengo
authors.initials: K
authors.lastname: Nakahata
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Matsunami
authors.forename: Chizuko
authors.initials: C
authors.lastname: Kobayashi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Omori
authors.forename: Hengjie
authors.initials: H
authors.lastname: Xu
authors.forename: Sabere
authors.initials: S
authors.lastname: Firdawes
authors.forename: Masahiro
authors.initials: M
authors.lastname: Fukuzawa
authors.forename: Shuji
authors.initials: S
authors.lastname: Miyagawa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D003001:Cloning, Molecular; D017244:Complement Factor I / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D003165:Complement System Proteins / Q000276:immunology / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D004285:Dogs; D022781:Hepatocytes / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D012697:Serine Endopeptidases / Q000276:immunology / Q000378:metabolism; D013045:Species Specificity; D013552:Swine / Q000276:immunology*; D014183:Transplantation, Heterologous
chemical_list: D003165:Complement System Proteins; D012697:Serine Endopeptidases; D017244:Complement Factor I