ABSTRACT
<p><b>OBJECTIVE</b>To establish ELISAs based on rLipL32/1-LipL21-OmpL1/2 fusion antigen of Leptospira interrogans for detecting specific IgG and IgM in serum of patients with leptospirosis.</p><p><b>METHODS</b>Microscope agglutination test(MAT) was performed to detect serum specimens from leptospirosis patients and to determine titers of rabbbit antiserum agaist rLipL32/1-LipL21-OmpL1/2 to reference standard strains of L. interrogans. By using rLipL32/1-LipL21-OmpL1/2, rLipL32/1, rLipL21 and rOmpL1/2 as the coated antigens, ELISAs for detecting specific serum IgM and IgG were established. The established ELISAs were applied to MAT-positive serum specimens from 107 patients with leptospirosis.</p><p><b>RESULT</b>The results of MAT confirmed that 66% (71/107) of the patients were infected with L.interrogans serogroup Icterohaemorrhagiae, and the rLipL32/1-LipL21-OmpL1/2 antiserum were able to agglutinate all 15 reference standard L.interrogans strains with 1 : 20approximate, equals1 : 160 titers. The positive rates of ELISAs using rLipL32/1-LipL21-OmpL1/2, rLipL32/1, rLipL21 or rOmpL1/2 as the antigen were 89.7%, 75.7%, 85.1% and 79.4% for detecting IgM, respectively, while 99.1%, 99.1%, 94.4% and 86.0% for detecting IgG, respectively. The positive detection rate of rLipL32/1-LipL21-OmpL1/2-IgM-ELISA was higher than those of the other three IgM detection ELISAs (P<0.05). The positive detection rate of rLipL32/1-LipL21-OmpL1/2-IgG-ELISA was higher than that of rOmpL1/2-IgG-ELISA (P<0.05), while there was no significant differnce with that of rLipL21-IgG-ELISA and rLipL32/1-IgG-ELISA (P>0.05).</p><p><b>CONCLUSION</b>The ELISAs using rLipL32/1-LipL21-OmpL1/2 as the antigen can be applied as a sensitive,specific and universal serological method for diagnosis of leptospirosis.rLipL32/1-LipL21-OmpL1/2-IgM-ELISA shows a definite value for early diagnosis of leptospirosis compared with the other ELISAs used in this study.</p>