Genes for immunodominant protein antigens are highly homologous in Mycobacterium tuberculosis, Mycobacterium africanum, and the vaccine strain Mycobacterium bovis BCG.
The relatedness of immunodominant protein antigens in Mycobacterium tuberculosis, M. africanum, and M. bovis BCG was investigated by comparing the genes that encode major protein antigens in M. tuberculosis with their counterparts in the other two mycobacteria. Genes encoding homologs of M. tuberculosis major protein antigens were isolated from M. africanum and M. bovis BCG by constructing lambda gt11 recombinant DNA expression libraries and screening them with murine monoclonal antibodies and DNA probes. The antibodies were directed against four major protein antigens of M. tuberculosis with molecular masses of 71, 65, 19, and 14 kilodaltons. The isolated M. africanum and M. bovis BCG DNA clones were mapped with restriction endonucleases, and the maps of the mycobacterial genes were confirmed by Southern analysis of mycobacterial genomic DNA. The restriction maps of DNA containing the four genes in M. tuberculosis, M. africanum, and M. bovis BCG are identical, indicating that the immunodominant proteins that they encode are highly homologous in the three mycobacteria. Thus, the immunity against tuberculosis engendered by M. bovis BCG vaccination could be provided, at least in part, by the immune response to these homologous antigens.
Lu
M C
MC
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
Lien
M H
MH
Becker
R E
RE
Heine
H C
HC
Buggs
A M
AM
Lipovsek
D
D
Gupta
R
R
Robbins
P W
PW
Grosskinsky
C M
CM
Hubbard
S C
SC
D000942:Antigens, Bacterial / Q000235:genetics*; D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes; D004269:DNA, Bacterial / Q000032:analysis; D004274:DNA, Recombinant / Q000032:analysis; D005798:Genes, Bacterial; D009161:Mycobacterium / Q000235:genetics* / Q000276:immunology; D009163:Mycobacterium bovis / Q000235:genetics* / Q000276:immunology; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000276:immunology; D009693:Nucleic Acid Hybridization; D012689:Sequence Homology, Nucleic Acid
D000942:Antigens, Bacterial; D004269:DNA, Bacterial; D004274:DNA, Recombinant; D004262:DNA Restriction Enzymes