Abstract: Objective The recombinant 38kD and 16kD protein of Mycobacterium tuberculosis (rTPA38 and rTPA16) as serological diagnostic reagents were evaluated.Methods The purified rTPA38 and rTPA16 were used to detect sera antibodies using enzyme-linked immunosorbent assay (ELISA),and using the PPD as control.Results In detecting the sera of 246 pulmonary tuberculosis patients,the sensitivity of rTPA38,rTPA16 and PPD was 66.3%,63.0% and 72.3% respectively.The specificity of rTPA38,rTPA16 and PPD in detecting of other groups:healthy controls,non tuberculosis respiratory patients,BCG-vaccinated healthy controls,was 97.6%, 96.8%, 86.0%;94.7%,93.1%,75.0% and 93.4%,85.7%,67.9% respectively.In detecting the sera of non tuberculosis respiratory patients and BCG vaccinated healthy controls,rTPA38 had much more positive reactions than that of PPD.To the sera of pulmonary tuberculosis patients,using combination of rTPA38 and rTPA16 as detecting antigens can improve the positive rate by 11.1%.Conclusion rTPA38,which can provide a satisfactory sensitivity and specificity,may become effective antigen in ELISA.A combination of rTPA38 and rTPA16 can improve the sensitivity.

Key words: Mycobacterium tuberculosis, 38kD Protein, 16kD Protein, ELISA, Serological diagnosis