title: Cloning of the gene encoding a 22-kilodalton cell surface antigen of Mycobacterium bovis BCG and analysis of its potential for DNA vaccination against tuberculosis.
abstract: Using spleen cells from mice vaccinated with live Mycobacterium bovis BCG, we previously generated three monoclonal antibodies reactive against a 22-kDa protein present in mycobacterial culture filtrate (CF) (K. Huygen et al., Infect. Immun. 61:2687-2693, 1993). These monoclonal antibodies were used to screen an M. bovis BCG genomic library made in phage lambdagt11. The gene encoding a 233-amino-acid (aa) protein, including a putative 26-aa signal sequence, was isolated, and sequence analysis indicated that the protein was 98% identical with the M. tuberculosis Lppx protein and that it contained a sequence 94% identical with the M. leprae 38-mer polypeptide 13B3 recognized by T cells from killed M. leprae-immunized subjects. Flow cytometry and cell fractionation demonstrated that the 22-kDa CF protein is also highly expressed in the bacterial cell wall and membrane compartment but not in the cytosol. C57BL/6, C3H, and BALB/c mice were vaccinated with plasmid DNA encoding the 22-kDa protein and analyzed for immune response and protection against intravenous M. tuberculosis challenge. Whereas DNA vaccination induced elevated antibody responses in C57BL/6 and particularly in C3H mice, Th1-type cytokine response, as measured by interleukin-2 and gamma interferon secretion, was only modest, and no protection against intravenous M. tuberculosis challenge was observed in any of the three mouse strains tested. Therefore, the 22-kDa antigen seems to have little potential for a DNA vaccine against tuberculosis, but it may be a good candidate for a mycobacterial antigen detection test.
authors.affiliation: Department of Virology, Pasteur Institute of Brussels, 1180 Brussels, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Lefèvre
authors.forename: O
authors.initials: O
authors.lastname: Denis
authors.forename: L
authors.initials: L
authors.lastname: De Wit
authors.forename: A
authors.initials: A
authors.lastname: Tanghe
authors.forename: P
authors.initials: P
authors.lastname: Vandenbussche
authors.forename: J
authors.initials: J
authors.lastname: Content
authors.forename: K
authors.initials: K
authors.lastname: Huygen
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000032:analysis / Q000235:genetics* / Q000276:immunology; D001500:BCG Vaccine / Q000276:immunology*; D003001:Cloning, Molecular; D016207:Cytokines / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008970:Molecular Weight; D019444:Vaccines, DNA / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D001500:BCG Vaccine; D016207:Cytokines; D019444:Vaccines, DNA