title: Serological analysis of C-terminal region of alpha antigen from Mycobacterium avium-intracellulare complex and Mycobacterium tuberculosis.
abstract: The alpha antigen, which is a 30 kDa protein secreted by mycobacterial species, is an immunodominant antigen. The C-terminal regions of alpha antigens are highly divergent, though there are regions where the amino acid sequence of alpha antigen is conserved. We investigated whether the C-terminal regions of the Mycobacterium avium alpha antigen, M. intracellulare alpha antigen and M. tuberculosis alpha antigen contain sequence-specific B-cell epitopes. The C-terminal regions of M. avium alpha antigen and M. intracelluare alpha antigen reacted to anti-M. avium alpha antigen but not to anti-M. tuberculosis alpha antigen derived from rabbits. Thus, M. avium and M. intracellulare have an antigenic determinant in common with rabbit. The C-terminal region of M. tuberculosis alpha antigen did not react to anti-M. avium alpha antigen or anti-M. tuberculosis alpha antigen. An enzyme-linked immunosorbent assay revealed that only the C-terminal region of M. avium alpha antigen reacted to the sera of two of six patients with M. avium-intracellulare (MAC) but not to the sera of patients with M. tuberculosis. In contrast, the C-terminal regions of M. intracellulare alpha antigen and M. tuberculosis alpha antigen were not recognized by the sera from patients with MAC or M. tuberculosis. This region of M. avium alpha antigen can produce a sequence-specific B-cell epitope in humans.
authors.affiliation: School of Dentistry, Nagasaki University, Sakamoto, Nagasaki City, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kitaura
authors.forename: N
authors.initials: N
authors.lastname: Ohara
authors.forename: M
authors.initials: M
authors.lastname: Naito
authors.forename: K
authors.initials: K
authors.lastname: Kobayashi
authors.forename: T
authors.initials: T
authors.lastname: Yamada
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000097:blood / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D018985:Epitopes, B-Lymphocyte / Q000276:immunology; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D008969:Molecular Sequence Data; D015269:Mycobacterium avium Complex / Q000737:chemistry / Q000276:immunology*; D015270:Mycobacterium avium-intracellulare Infection / Q000276:immunology / Q000382:microbiology*; D009169:Mycobacterium tuberculosis / Q000737:chemistry / Q000276:immunology*; D010455:Peptides / Q000276:immunology; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000276:immunology; D016415:Sequence Alignment; D014376:Tuberculosis / Q000276:immunology / Q000382:microbiology*; D001616:beta-Galactosidase
chemical_list: D000942:Antigens, Bacterial; D018985:Epitopes, B-Lymphocyte; D007106:Immune Sera; D010455:Peptides; D011993:Recombinant Fusion Proteins; C052242:alpha antigens, Mycobacterium; D001616:beta-Galactosidase