[The detection of antibodies to Mycobacterium tuberculosis and its reactivity to three different purified protein derivative by ELISA].

The specific PPD IgG antibodies in serum of patients with pulmonary tuberculosis and its reactivity to PPD of Mycobacterium tuberculosis M. bovis and M. avium were detected by ELISA. The results showed that the antibody level and positive rate of patients with pulmonary tuberculosis significantly increased than those of normal subjects. Specific antibody level and its positive rate were higher in hospitalized patients than those treated in clinic and both were higher in sputum positive cases than in sputum negative one. There was cross-reactivity among three different PPD. Absorption black test indicated that M. tuberculosis PPD had good specificity. PPD should be further purified in order to make ELISA as a useful serodiagnostic tool.