[Nucleic acid components of mycobacteria: recent studies on secreted protein genes].

Among the nucleic acid components of mycobacteria, secreted protein genes have been attractive targets in relation to the role in the bacteria-host cell interaction. The alpha antigen gene family is of particular interest from its evolutional constitution process and as a candidate of protective antigen for tuberculosis (TB). Recent studies on DNA vaccination revealed that the antigen 85A, a member of the alpha antigen family, could induce protective immunity against TB. The other studies on the development of recombinant BCG vaccines demonstrated that alpha antigen gene is applicable to a foreign antigen carrier which could obtain protective immunity against human immunodeficiency virus and malaria parasite infections. In this paper, advanced applications of such mycobacterial secreted protein genes are reviewed.