[A preliminary report on diagnostic complementarity of gut-associated and egg-associated antigenemia in schistosomiasis japonica].

With Hyroxylapatite purified preparations and BACH (biotin aminocapryl hydrazide) biotinylated McAbs, 274-2H10 and 273-2H1, recognizing different egg-associated epitopes, biotin-avidin (BA) involved alkaline phosphatase (AP) ELISA with detecting sensitivities reaching nanogram levels (10(-9), were set up. The detectable limit for crude preparations of Schistosoma japonicum SEAJ-TCA in 2H10-ELISA achieved 1. 0.3. 2 ng/ml, in which only S. japonicum specific egg antigens were efficiently detected, whereas with 2H1-ELISA, which could detect SEA-TCA of both S. japonicum and S. mansoni species, an end point of detecting 3.2 ng/ml was obtained. Repeated tests with human serum groups revealed very significant differences of extinction OD readings between patients and normal individuals. For detection combinations, a previously established anti-CAA homologous AP-ELISA system was parallelly used for gut-associated antigenemia determinations. Taking the mean extinction OD reading of a parallel normal serum group plus 3 SD as corresponding cut off values, 3 patient groups (n = 82, 52, 39) from different areas of transmission intensity were subjected to accumulating determinations for egg- and gut-associated antigenemia. Improved detectabilities to variable extent were achieved in either of the 2 or 3 combinations. The study thus demonstrated that the diagnostic efficiency for human schistosomiasis could be improved by multi-epitope detections for more than one target molecule using corresponding McAbs, especially in areas where the transmission intensity of the disease is comparatively lower.