Comparative studies with various substrains of Mycobacterium bovis BCG on the production of an antigenic protein, MPB70

Abstract

A protein, isolated and purified from the unheated culture filtrate of Mycobacterium bovis BCG (substrain Tokyo 172) and designated MPB70, elicited a delayed skin reaction in guinea pigs sensitized with viable cells of BCG but not in those sensitized with heat-killed cells. The skin reaction reached the maximum 4 to 8 weeks after the inoculation of the BCG and then decreased gradually, resulting in conversion to negative after 20 weeks, whereas the skin reaction to purified protein derivative (PPD) continued to be positive. Guinea pigs immunized with viable cells of various substrains of BCG were skin tested with MPB70 and PPD. Guinea pigs immunized with the BCG substrain Tokyo 172 and the substrain Moreau (Brazil) showed strong delayed skin reactions to both MPB70 and PPD. On the other hand, guinea pigs immunized with the Pasteur substrain 1173P2, the Glaxo substrain 1077, the Copenhagen substrain 1331, the Tice substrain, or the Beijing substrain 64-42 showed negative skin reactions to MPB70, whereas they were strongly positive to PPD. In a two-dimensional acrylamide gel electrophoretic analysis of proteins from the culture filtrates of the BCG substrains, the culture filtrates of the Tokyo and Moreau substrains showed the spot of MPB70 on the gel slabs, whereas those of the other BCG substrains did not.

Expression of Mycobacterium tuberculosis MPT64 in recombinant Myco. smegmatis: purification, immunogenicity and application to skin tests for tuberculosis

“…tuberculosis and BCG, including the Myco. tuberculosis 38-kD [24], MPB70 [25] and the 10-kD ESAT-6 proteins [26]. A combination of these Myco.…”

Homology Between the MPB70 and MPB83 Proteins of Mycobacterium bovis BCG

“…Immunogenicity with regard to induction of B cell responses is shown by generation of polyclonal and monoclonal antibodies after immunization and increased antibody levels following infection with virulent M.bovis [2, 7-9, 11, 18-24]. Induction of T cell responses has been demonstrated by development of delayed type hypersensitivity (DTH) in vivo as well as increased T cell proliferation and interferon-7 production in vitro [1,6,7,9,11,[18][19][20]. MPB70 is a major constituent of bovine PPD [7,25].…”

“…BCG substrains may be divided into high-and lowproducers of MPB70, BCG Tokyo and BCG Copenhagen being prototype high-producer and low-producer substrains, respectively [2,6]. Virulent strains of M.bovis produce and secrete large amounts of MPB70 and there is substantial formation of antibodies to MPB70 in cattle with M.bovis infection [7][8][9], while Mycobacterium tuberculosis culture fluids only contain negligible amounts of the protein.…”

Cloning and Sequencing of a Unique Antigen MPT70 from Mycobacterium tuberculosis H37Rv and Expression in BCG Using E. coli‐Mycobacteria Shuttle Vector

“…Moreau. and Moscow [18,19]. Its molecular mass was estimated to be approximately 22 kDa and it formed up to 10% of the total secreted proteins, possibly as much as 23%.…”

“…It could not be detected in A/, tuberculosis and BCG strains such as Pasteur, Glaxo, Copenhagen. Chicago, and Prague [18,19]. In crossed radioimmunoassay (RIA), however, antibody against MPB70 was able to detect this protein even in those organisms, although reactions were only \% or less of the amount in BCG Tokyo [20].…”