ULTRASTRUCTURAL IMMUNOLOCALIZATION OF 2 CIRCULATING EGG ANTIGENS IN MIRACIDIA OF SCHISTOSOMA-MANSONI

In the present study ultrastructural immunocytochemical techniques hav e been used to localize the cells producing two soluble egg antigens p resent in the hatching fluid of Schistosoma mansoni, using two recentl y described monoclonal antibodies (MAbs). In the miracidium of S. mans oni, the one apical and the two lateral unicellular glands showed immu noreactivity for the egg antigens, using a post-embedding immunogold t echnique. Immunoreactivity was associated with the contents of vesicle s for both the MAbs, although the intravesicular distribution was not identical. This difference in ultrastructural staining pattern provide s additional evidence that the two MAbs are binding with different epi topes of the same antigen or with different antigens altogether. The f inding of free unbound label around the embedded miracidium is consist ent with secretion having been released from the glands.