Study of fluorescent antibodies directed against the gut epithelium of Schistosoma mansoni .6. Immunolocalisation of a carbohydrate epitope at the different stage of the parasite evolution

In the course of previous works, we described on IgM monoclonal antibody directed to a carbohydrate epitope located on the gut epithelium surface of the Schistosoma mansoni adult worm. We provided evidence that this epitope was present in all stages of the parasite and was particularly abundant in eggs. The current work was performed in order to specify the epitope localisation, at each siege, by immunohistochemical techniques. The epitope appears to be located on the peripheral membranes of the adult worm, while it is produced by the alive miracidium in the eggs located in the tissues and subsequently spied out inside the periovular granuloma. Moreover, in adult worms, the observed structure presents itself as a soluble form in organic solvents, on the other hand, in eggs, the epitope was essentially found made of an hydrosoluble substance. These datas can explain why, in experimentally infected mice, the epitope is mainly determined in urines at the sixth week of infestation, when eggs are settled down in the tissues. Besides, the inhibition of the monoclonal antibody fixation by a pentose which contains the Lewis X antigen, pointed out that the carbohydrate structure recognised by the monoclonal antibody could be the Lewis X antigen or a very closed structure.