Studies On The Evaluation Of The Signaling Protein 14-3-3 Of Schistosoma Japonicum (Chinese Mainland Strain) And Its Monoclonal Antibody In Diagnosis For The Schistosomiasis

Objective: To evaluate the diagnostic value of recombinant signaling protein 14-3-3 of Schistosoma japonicum (rSj14-3-3) and its monoclonal antibody in the diagnosis of schistoisomiasis. Methods: rSjl4-3-3 was prepared from pETZSa/E.coli BL21 by IPTG induction and purified in scale and the hybridoma cell strain which secreted anti-rSj14-3-3 McAb was screened. The monoclonal antibody against rSjl4-3-3 was harvested through injection of BALB/c mice with hybridoma cells. Specific antibodies to rSj 14-3-3 in sera of patients with acute and chronic schistosomiasis and those of infected rabbits with various parasite burden following chemotheraphy of praziquantel were detected with purified rSj 14-3-3 antigen by indirect enzyme-linked immunoadsordent assay( IELISA).Simultaneously, the circulating Sj 14-3-3 were tested with anti-Sj 14-3-3 monoclonal antibody(McAb)by polyclonal -monoclonal antibody sandwich ELISA(P-M-ELISA).By contrast with soluble egg antigen-ELISA (SEA-ELISA),the value of rSj 14-3-3 and its McAb in diagnosis for the schistosomiasis was evaluated. Results: Purified rSj 14-3-3 proteins were obtained vastly.The McAb against rSj 14-3-3 antigen was obtained and its subclass was identified as IgGl.The liter of peritoneal exudate was 1:1 X 106.There is no significant difference among the sensibitity of rSjl4-3-3-ELlSA, P-M-ELISA and SEA-ELISA in diagnosis for schistosomiasis(the positive rate of rSj14-3-3-ELISA,P-M-ELISA and SEA-ELISA intesting the sera from 45 proved cases with acute schistosomiasis were 100%,100%and 97.8%,respectively;while in 45 proved cases with chronic schistosomiasis were 93.3%,95.6%,95.6%,respectively,P>0.05), whereas there is significant difference in specificity of these methods in normal persons and the individuals with clonorchiasis and hook worm disease(P<0.05,for instance, no false positive reaction was detected in 60 normal controls with rSj14-3-3-ELISA and P-M-ELISA,in contrast with the 6.7%(4/60) false positive rate of SEA-ELISA) . Results varied in detection of circulating antigens and its antibodies in sera of patients with schistosomiasis after 2,4,6,and 12 months of treatment and infected rabbits following effective chemotheraphy. Conclusions: The rSj 14-3-3 protein and its monoclonal antibody showed higher sensitivity and specificity for the diagnosis of schistoisomiasis, suggesting that the detection of circulating Sj 14-3-3 antigen and anti-Sj 14-3-3 antibodies in sera of patients infected with S.japonicum is a practicable and convenient mothod for the diagnosis of this disease.