Immunoreactivity of a cytokeratin-related polypeptide from adult Schistosoma mansoni

A saline extract (SE) derived from living adult Schistosoma mansoni confers high levels of resistance to challenge infection in mice and rabbits. We have carried out a number of experiments to analyse the composition of SE and to define the proteins that are rapidly released from the parasite. One of these proteins, with apparent molecular mass of 62 kDa, is recognized by polyclonal and monoclonal antibodies raised against high molecular mass cytokeratins from human epidermal cells. Immunocytochemical studies revealed a tegumental staining using the anti-cytokeratin antibody. Moreover, sera from schistosomiasis patients, as well as those from animals immunized with SE, were able to recognize this 62 kDa polypeptide as shown by immunoblot assays. These results suggest the existence of cytokeratin-containing filaments in the schistosome.