IMMUNOLOGICAL CHARACTERIZATION OF 2 MONOCLONAL-ANTIBODIES REACTIVE WITH REPETITIVE CARBOHYDRATE EPITOPES OF CIRCULATING SCHISTOSOMA-MANSONIEGG ANTIGEN

A panel of 60 monoclonal antibodies (MAbs) reactive with repetitive ep itopes of species-specific Schistosoma mansoni soluble egg antigen (SE A) was tested for performance in detecting circulating egg antigens. T wo MAbs, 114-5B1-A and 114-4D12-A, which were highly reactive with two different repetitive carbohydrate epitopes of soluble egg antigen, we re found to detect circulating egg antigen in the sera of S. mansoni- infected mice. The two MAbs also showed strong reactivity with two hig h M(r) cercarial antigens present on the cercarial and schistosomular surface, while in the adult worms, antigens in the parenchyma were rec ognized. In two sandwich enzyme-linked immunosorbent assays (ELISA-5B1 and ELISA-4D12), each MAb was used as capture antibody and as conjuga te, which resulted in assays with a lower detection level (0.2-0.4 ng) of the trichloroacetic acid-soluble fraction of soluble egg antigen ( SEA-TCA)/ml. The antigen component(s) detected by ELISA-5B1 and ELISA- 4D12 were 10,000 and 40,000 times more concentrated in the egg antigen than in the adult worm antigen, respectively. With both assays, in se rum of heavily S. mansoni-infected mice, antigen became detectable fro m eight weeks postinfection (PI) onwards, with a striking increase at nine weeks PI.