An immunoregulatory human monoclonal antibody in schistosomiasis japonica.

A series of human monoclonal antibodies were generated using splenocytes from a Chinese patient with chronic schistosomiasis who had undergone splenectomy as part of a portacaval decompression operation. Splenocytes were transformed in bulk culture by Epstein Barr virus and transformants fused with the HMMA 2.11 TG/O cell line. Twenty individual IgG antiworm and egg antibody-producing hybridomas were generated and screened for antigen reactivity by Western blot and for suppression of antigen-induced blastogenesis of murine splenocytes from Schistosoma japonicum-infected animals. Only one IgG clone significantly suppressed (56% P less than 0.05) soluble egg antigen (SEA)-induced blastogenesis. This human monoclonal antibody bound a 50 kD carbohydrate antigen on Western blot analysis, binding both the adult worm and egg antigens of this parasite. The non-regulatory monoclonal antibodies bound this same molecule present in adult worms but not the corresponding molecule in a preparation of soluble eggs. Thus, specific immunoregulatory epitopes can be identified by human monoclonal antibodies generated from patients with chronic disease.