Previously, we had identified a recombinant bacteriophage from a lgt11 gene library which expressed an immunogenic Mycobacterium kansasii antigen (MK35). We had also demonstrated that MK35 is reactive against sera from patients with mycobacterial disease and evokes a large skin test response in sensitized guinea pigs. In FY92, we have completed the DNA sequence of the gene encoding MK35. Nucleotide sequence analysis has indicated that MK35 is a 26 kDa lipoprotein. Using polymerase chain reaction methodologies, we have identified homologous genes from M. tuberculosis and M. avium. These genes are currently being characterized.