title: Immunochemical evidence that human apoB differs when expressed in rodent versus human cells.
abstract: LDL from human apolipoprotein B-100 (apoB-100) transgenic (HuBTg+/+) mice contains more triglyceride than LDL from normolipidemic subjects. To obtain novel monoclonal antibody (MAb) probes of apoB conformation, we generated hybridomas from HuBTg+/+ that had been immunized with LDL isolated from human plasma. One apoE-specific and four anti-apoB-100-specific hybridomas were identified. Two MAbs, 2E1 and 3D11, recognized an epitope in the amino-terminal 689 residues of apoB in native apoB-containing lipoproteins (LpBs) from human plasma or from the supernatant of human hepatoma HepG2 cells, but did not react with LpB from HuBTg+/+ mice or LpB secreted by human apoB-100-transfected rat McArdle 7777 hepatoma cells. 2E1 reacted weakly and 3D11 reacted strongly with apoB from HuBTg+/+ mice after SDS-PAGE. The lack of expression of the 2E1 and 3D11 epitopes on native LpB from HuBTg+/+ mice did not solely reflect the abnormal lipid composition of murine LpB. Both epitopes were detected in all human plasma samples tested and in all human plasma LpB classes. Therefore, human apoB expressed by rodent hepatocytes or hepatoma cells appears to adopt a different conformation or undergoes different posttranslational modification than apoB expressed in human hepatocytes or hepatoma cells.
authors.affiliation: Lipoprotein and Atherosclerosis Research Group and the Department of Pathology, University of Ottawa Heart Institute, Ottawa, Ontario, Canada.
authors.forename: Xingyu
authors.initials: X
authors.lastname: Wang
authors.forename: Vinita
authors.initials: V
authors.lastname: Chauhan
authors.forename: Anh T
authors.initials: AT
authors.lastname: Nguyen
authors.forename: Joshua
authors.initials: J
authors.lastname: Schultz
authors.forename: Jean
authors.initials: J
authors.lastname: Davignon
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Young
authors.forename: Jan
authors.initials: J
authors.lastname: Boren
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Innerarity
authors.forename: Hui
authors.initials: H
authors.lastname: Rutai
authors.forename: Ross W
authors.initials: RW
authors.lastname: Milne
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D001055:Apolipoproteins B / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D002460:Cell Line; D000939:Epitopes / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D015870:Gene Expression; D006801:Humans; D006825:Hybridomas / Q000276:immunology; D007120:Immunochemistry; D008077:Lipoproteins, LDL / Q000276:immunology; D051379:Mice; D008822:Mice, Transgenic; D011499:Protein Processing, Post-Translational; D011863:Radioimmunoassay
chemical_list: D000911:Antibodies, Monoclonal; D001055:Apolipoproteins B; D000939:Epitopes; D008077:Lipoproteins, LDL