IMMUNOELECTRON MICROSCOPIC LOCALIZATION OF A CIRCULATING ANTIGEN IN THE EXCRETORY SYSTEM OF SCHISTOSOMA-MANSONI - ULTRASTRUCTURAL-LOCALIZATION STUDIES OF THE EXCRETORY SYSTEM OF SCHISTOSOMA-MANSONI

In this study the excretory system of Schistosoma mansoni was ultrastr ucturally examined with a recently described monoclonal antibody (mAb) against a circulating antigen. In previous studies this mAb was found to have affinity for the excretory system. Strong immunoreactivity wa s found on the flagella of the flame cells and of the collecting ducts throughout the worm. The eggshell and the space between the miracidiu m and the eggshell showed strong reactivity with a declining gradient towards the exterior, suggesting a secretion process. In cercariae, im munoreactivity was restricted to the tegument, whereas in schistosomul a the labeling pattern resembled that of the adult worm, demonstrating positive reactivity of the flame cells and no immunostaining of the t egument. This stage-dependent differential expression of different ant igens in the excretory system and in the tegument could suggest a matu ration process of the excretory system.