title: Characterization, sequence determination, and immunogenicity of a 64-kilodalton protein of Mycobacterium bovis BCG expressed in escherichia coli K-12.
abstract: We report the DNA sequence of a previously cloned Mycobacterium bovis BCG gene encoding an immunogenic 64-kilodalton protein. This protein, MbaA, was purified from overproducing Escherichia coli K-12 cells, and the presence of antibodies to MbaA in human sera was determined by an enzyme-linked immunosorbent assay. In about 80% of serum samples from tuberculosis patients and in about 60% of samples from BCG-vaccinated individuals, significant levels of anti-MbaA antibodies were found. Surprisingly, in about 30% of the control serum samples obtained from children, anti-MbaA antibodies were also observed. Guinea pigs sensitized with M. bovis BCG or MbaA showed a delayed-type hypersensitivity reaction after challenge with purified MbaA, supporting the previously observed strong reactivity of human T-cell clones with this, for mycobacteria, common antigen.
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D000917:Antibody Formation; D001426:Bacterial Proteins / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D001483:Base Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000235:genetics; D006168:Guinea Pigs; D006801:Humans; D009163:Mycobacterium bovis / Q000235:genetics*; D014397:Tuberculosis, Pulmonary / Q000276:immunology; D014611:Vaccination
chemical_list: D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins