Comparison of Different Recombinant Antigen-Based Enzyme Immunoassays for Detection of Antibodies Against Treponema Pallidum

Objective To compare the enzyme immunoassays(EIA)based on a single recombinant T reponema pallidum (TP)antigen Tp47,Tp42 or Tp17 with that using combination of the three recombinant Tp ant igens.Methods Anti-Tp negaove and 10 anti-Tp positive sera tested by TPHA(Treponema pallidum hemagg lutination)were detected by both the EIA based on combination of the 3 recombinant Tp antigens(Tp47,Tp42 and Tp17)and the EIA using a single Tp protein (Tp47,or Tp42,or Tp17).Results The sensitivity of EIA based on a single antigen Tp47,Tp42,or Tp17 was 100%(11/11),100%(11/11)and 90.9%(10/11),with the speciacity of 96.4%(27/28),100%(28/28)and 96.4%(27/28),respectively.The sensitivity and the specificity of EIA based on combination of the three Tp antigens were 100%(11/11)and 100%(28/28),respectively.Conclusion There was some false negative and false positive reactivity with the EIA based on a single recombinant antigen for diagnosis of syphilis.The sensitivity of EIA based on combination of the three antigens (Tp47,Tp42 and Tp17)for detection of anti-Tp antibody was higher than that of the EIA with a single recombinant Tp antigen.