Abstract: Objective To study the immunogenecity of recombinant EIS protein,a novel antigen encoded by enhanced intracellular survival gene of Mycobacterium tuberculosis,and its possible application to screen the active tuberculosis. Methods The purified recombinant EIS protein was used as antigen to detect the antibody responses in the sera from the patients with pulmonary tuberculosis,healthy donors and patients with lung disease other than tuberculosis by ELISA.Results:The level of antibody responses was significant higher in the sera from patients with pulmonary tuberculosis than that from healthy donors and patients with non-tuberculosis lung disease.The titer of anti-EIS antibody in the sera from patients with pulmonary tuberculosis had not significant changed during the anti-tuberculosis chemotherapy. Conclusion EIS antigen may be a useful antigen for screening the active tuberculosis.

Key words: ElS protein, Pulmonary tuberculosis/diagnosis, Antibody response