Mapping of the T and B cell epitopes of the Mycobacterium bovis protein, MPB70

A clone coding for the entire gene for the Mycobacterium bovis protein antigen MPB70 was used to produce a series of overlapping subclones by making a series of deletions from the 3' end of the gene. The subclones expressed incomplete MPB70 proteins as fusions with glutathione-S-transferase. The insert DNA was sequenced to determine the extent of the deletion and the proteins expressed by the clones were examined for the presence of T cell and B cell epitopes. T cell epitopes were mapped by measuring the ability of recombinant antigens to stimulate gamma interferon (gamma-IFN) production in a whole blood culture system. gamma-IFN production was measured using a sandwich enzyme immunoassay specific for bovine gamma-IFN. B cell epitopes were mapped with a series of anti-MPB70 monoclonal antibodies using an indirect enzyme immunoassay.