EVIDENCE FOR ABSENCE OF THE MPB64 GENE IN SOME SUBSTRAINS OF MYCOBACTERIUM-BOVIS BCG

Substrains of Mycobacterium bovis BCG have been divided in two major g roups, high producers and low producers of the secreted proteins MPB64 and MPB70. Of these, Mycobacterium tuberculosis secretes only the ana log MPT64 during growth on Sauton medium. It has been confirmed that h igh-producer and low-producer substrains of BCG as well as M. tubercul osis contain the gene for the MPB/MPT70 protein. By contrast, polymera se chain reaction and hybridization experiments are reported here whic h indicate that the MPB64 gene is absent in the BCG substrains Copenha gen, Pasteur, Glaxo, and Tice, in which previous methods did not permi t distinction between secretion of small amounts or absence of the pro tein in culture fluids.