THE IMMUNODOMINANT 38-KDA LIPOPROTEIN ANTIGEN OF MYCOBACTERIUM-TUBERCULOSIS IS A PHOSPHATE-BINDING PROTEIN

Several antigens of Mycobacterium tuberculosis have been identified by monoclonal antibodies and are being exploited in the development of i mproved vaccines and diagnostic reagents, but none has been linked to a specific function. Herein we report that the 38-kDa extra cellular l ipoprotein antigen, the most potent immunogen of the mycobacteria, is a phosphate-binding protein with features very similar to those of the well characterized periplasmic phosphate-binding protein of Escherich ia coli which serves as an initial receptor for active transport. This is also the first report definitely linking a function of a binding p rotein anchored to a membrane nd found in other that Gram-negative bac teria.