Abstract: lep polypeptides and DNA (RNA) encoding such lep and a procedure for producing such polypeptides by recombinant techniques is disclosed. Also disclosed are methods for utilizing such lep for the treatment of infection, particularly bacterial infections. Antagonists against such lep and their use as a therapeutic to treat infections, particularly bacterial infections are also disclosed. Also disclosed are diagnostic assays for detecting diseases related to the presence of lep nucleic acid sequences and the polypeptides in a host. Also disclosed are diagnostic assays for detecting polynucleotides encoding leader peptidase and for detecting the polypeptide in a host.