title: Antigen S1, encoded by the MIC1 gene, is characterized as an epitope of human CD59, enabling measurement of mutagen-induced intragenic deletions in the AL cell system.
abstract: S1 cell membrane antigen is encoded by the MIC1 gene on human chromosome 11. This antigen has been widely used as a marker for studies in gene mapping or in analysis of mutagen-induced gene deletions/mutations, which utilized the human-hamster hybrid cell-line, AL-J1, carrying human chromosome 11. Evidence is presented here which identifies S1 as an epitope of CD59, a cell membrane complement inhibiting protein. E7.1 monoclonal antibody, specific for the S1 determinant, was found to react strongly with membrane CD59 in Western blotting, and to bind to purified, urinary form of CD59 in ELISAs. Cell membrane expression of S1 on various cell lines always correlated with that of CD59 when examined by immunofluorescent staining. In addition, E7.1 antibody inhibited the complement regulatory function of CD59. Identification of S1 protein as CD59 has increased the scope of the AL cell system by enabling analysis of intragenic mutations, and multiplex PCR analysis of mutated cells is described, showing variable loss of CD59 exons.
authors.affiliation: Microbial Immunology Group, Centre for Veterinary Science, University of Cambridge, UK.
authors.forename: A B
authors.initials: AB
authors.lastname: Wilson
authors.forename: D
authors.initials: D
authors.lastname: Seilly
authors.forename: C
authors.initials: C
authors.lastname: Willers
authors.forename: D B
authors.initials: DB
authors.lastname: Vannais
authors.forename: M
authors.initials: M
authors.lastname: McGraw
authors.forename: C A
authors.initials: CA
authors.lastname: Waldren
authors.forename: T K
authors.initials: TK
authors.lastname: Hei
authors.forename: A
authors.initials: A
authors.lastname: Davies
mesh_terms: D000818:Animals; D018957:CD59 Antigens / Q000235:genetics* / Q000276:immunology; D015815:Cell Adhesion Molecules / Q000235:genetics* / Q000276:immunology; D002880:Chromosomes, Human, Pair 11 / Q000235:genetics; D003169:Complement Inactivator Proteins / Q000235:genetics / Q000276:immunology; D006224:Cricetinae; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000235:genetics; D006801:Humans; D006822:Hybrid Cells; D016296:Mutagenesis / Q000235:genetics; D009152:Mutagenicity Tests / Q000379:methods*; D009153:Mutagens; D009363:Neoplasm Proteins / Q000235:genetics* / Q000276:immunology; D015800:Protozoan Proteins; D017384:Sequence Deletion
chemical_list: D018957:CD59 Antigens; D015815:Cell Adhesion Molecules; D003169:Complement Inactivator Proteins; D000939:Epitopes; C105877:MIC1 protein, Toxoplasma gondii; D009153:Mutagens; D009363:Neoplasm Proteins; D015800:Protozoan Proteins; C081763:sarcoma-associated antigen S1