MPB70 and MPB83 are among the most characteristically exported proteins def
ining a strongly expressed phenotype of Mycobacterium bovis. These proteins
are known to be homologous to osteoblast-specific factor 2. By in vitro cu
lture of mycobacteria they appear to have a limited species distribution an
d to be relatively specific for M. bovis. Virtually identical gents are how
ever, present in Mycobacterium tuberculosis. In order to facilitate further
research into the immunobiology of these proteins and their potential appl
ication for differential diagnosis of tuberculosis as a result of M. bovis,
we describe the reactivities of 20 monoclonal antibodies (MoAbs) to these
proteins. Immunizing with bovine PPD generated 10 MoAbs. These antibodies r
eacted preferentially with the soluble MPB70 antigen using reducing conditi
ons in SDS-PAGE with western blotting. Ten MoAbs were generated by immunizi
ng mice with fractions derived from a whole cell sonic extract of M. bovis.
These antibodies reacted preferentially with the surface exposed MPB83 lip
oglycoprotein.