title: A novel monoclonal antibody to characterize pathogenic polymers in liver disease associated with alpha1-antitrypsin deficiency.
abstract: Alpha(1)-antitrypsin is the most abundant circulating protease inhibitor. The severe Z deficiency allele (Glu342Lys) causes the protein to undergo a conformational transition and form ordered polymers that are retained within hepatocytes. This causes neonatal hepatitis, cirrhosis, and hepatocellular carcinoma. We have developed a conformation-specific monoclonal antibody (2C1) that recognizes the pathological polymers formed by alpha(1)-antitrypsin. This antibody was used to characterize the Z variant and a novel shutter domain mutant (His334Asp; alpha(1)-antitrypsin King's) identified in a 6-week-old boy who presented with prolonged jaundice. His334Asp alpha(1)-antitrypsin rapidly forms polymers that accumulate within the endoplasmic reticulum and show delayed secretion when compared to the wild-type M alpha(1)-antitrypsin. The 2C1 antibody recognizes polymers formed by Z and His334Asp alpha(1)-antitrypsin despite the mutations directing their effects on different parts of the protein. This antibody also recognized polymers formed by the Siiyama (Ser53Phe) and Brescia (Gly225Arg) mutants, which also mediate their effects on the shutter region of alpha(1)-antitrypsin.
  
  
  CONCLUSIONS
  Z and shutter domain mutants of alpha(1)-antitrypsin form polymers with a shared epitope and so are likely to have a similar structure.
authors.affiliation: Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/Medical Research Council Building, Cambridge, UK. mariaelena.mirandabanos@uniroma1.it
authors.forename: Elena
authors.initials: E
authors.lastname: Miranda
authors.forename: Juan
authors.initials: J
authors.lastname: Pérez
authors.forename: Ugo I
authors.initials: UI
authors.lastname: Ekeowa
authors.forename: Nedim
authors.initials: N
authors.lastname: Hadzic
authors.forename: Noor
authors.initials: N
authors.lastname: Kalsheker
authors.forename: Bibek
authors.initials: B
authors.lastname: Gooptu
authors.forename: Bernard
authors.initials: B
authors.lastname: Portmann
authors.forename: Didier
authors.initials: D
authors.lastname: Belorgey
authors.forename: Marian
authors.initials: M
authors.lastname: Hill
authors.forename: Susan
authors.initials: S
authors.lastname: Chambers
authors.forename: Jeff
authors.initials: J
authors.lastname: Teckman
authors.forename: Graeme J
authors.initials: GJ
authors.lastname: Alexander
authors.forename: Stefan J
authors.initials: SJ
authors.lastname: Marciniak
authors.forename: David A
authors.initials: DA
authors.lastname: Lomas
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D004721:Endoplasmic Reticulum / Q000378:metabolism; D000939:Epitopes / Q000276:immunology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007567:Jaundice, Neonatal / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008107:Liver Diseases / Q000378:metabolism*; D008297:Male; D009154:Mutation / Q000235:genetics; D011108:Polymers / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D000515:alpha 1-Antitrypsin / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D019896:alpha 1-Antitrypsin Deficiency / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D011108:Polymers; D000515:alpha 1-Antitrypsin