CANDIDATE ANTIGENS FOR IMPROVED SERODIAGNOSIS OF TUBERCULOSIS

Objective: To explore the possibility that an analysis of antibody spe cificity to separated components of mycobacteria in a group of tubercu lous patients may reveal a combination of target antigens whose antibo dies could form the basis of a useful serodiagnostic test. Design: Imm unoblots of 1-dimensional (SDS-PAGE) and-dimensional (isoelectric focu sing/SDS-PAGE) separation of antigenic extracts of Mycobacterium tuber culosis H37Rv (MTSE) and M. bovis bacille Calmette-Guerin (BCG) (MBSE) with 52 tuberculous and 59 BCG-vaccinated control human sera were ana lyzed for band and spot reactivity patterns that are indicative of inf ection with M. tuberculosis. Results: Reactivity to antigens banding i n the 10-18 kDa, 37-43 kDa and 70-90 kDa regions allowed a good discri mination between patients and normal subjects. Patients' sera reacting with antigens in the 22-30 and 70-88 kDa regions differentiated respo nses to MTSE and MBSE. In 2-D immunoblotting, patients' sera only reac ted with antigens separating at similar to pI 6.5/26-28 kDa, pI 4.8/38 kDa and pI 6.5/70-79 kDa position and the responses were specific for M. tuberculosis (MTSE). Conclusion: These results provide evidence th at a combination of these M. tuberculosis antigens may be a useful bas is for developing a diagnostic antibody test. Additionally, they may h elp to define antigens, and host antibody responses that are specific to one but not the other of the two closely related species.