title: Association of a major protein antigen of Mycoplasma arthritidis with virulence.
abstract: Mycoplasma arthritidis causes acute polyarthritis in rats and chronic proliferative arthritis in mice. M. arthritidis-induced arthritis serves as a model for arthritis caused by infectious agents and as a model for examining the role of the superantigen MAM (M. arthritidis T-cell mitogen) in the development of autoimmunity. M. arthritidis strain 158-1 is a spontaneous mutant of strain 158 that has a drastic reduction in virulence. We show that the mutant is missing a major antigen of 47 kDa (P47) and has acquired a protein of 67 kDa (P67). P47 and P67 partitioned into the detergent phase by extraction with Triton X-114. Coomassie blue staining of sodium dodecyl sulfate-polyacrylamide gels show that P67 is produced in abundance. Analysis of gel-purified P67 by mass spectrometry led to its identification as a lipoprotein (the open reading frame [ORF] 619 gene product) predicted from the genome sequence of M. arthritidis. PCR analysis of genomic DNA from 158 and 158-1 indicates that P47 and P67 are encoded by the same ORF 619 gene and differ only in the number of repeats in a tandem repeat region. By two-dimensional polyacrylamide gel analysis, no protein differences were detectable between 158 and 158-1 other than P47 and P67. Collectively, the data suggest that the tandem repeat region of P47 and P67 influences disease outcome.
authors.affiliation: Department of Genetics, KAUL, Room 720, University of Alabama at Birmingham, Birmingham, AL 35294-0024, USA.
authors.forename: A-H T
authors.initials: AH
authors.lastname: Tu
authors.forename: B
authors.initials: B
authors.lastname: Clapper
authors.forename: T R
authors.initials: TR
authors.lastname: Schoeb
authors.forename: A
authors.initials: A
authors.lastname: Elgavish
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.forename: L
authors.initials: L
authors.lastname: Liu
authors.forename: H
authors.initials: H
authors.lastname: Yu
authors.forename: K
authors.initials: K
authors.lastname: Dybvig
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D005260:Female; D013058:Mass Spectrometry; D051379:Mice; D008811:Mice, Inbred DBA; D008969:Molecular Sequence Data; D045645:Mycoplasma arthritidis / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity*; D010587:Phagocytosis; D051381:Rats; D011917:Rats, Inbred Lew; D020080:Tandem Repeat Sequences; D014774:Virulence
chemical_list: D000942:Antigens, Bacterial