Adult schistosome worm-derived antigenic substance and method of obtaining same

A vaccine for immunizing mammals against infection by schistosomes comprising an antigenic material containing saline extract of live adult schistosomes obtained by the steps of:

• perfusing fresh, living adult schistosome worms from a host with a buffered saline solution;
• rinsing the perfused worms with from one to three low volume buffered saline solutions to remove only blood and non-worm blood solids, said rinsing not washing away any significant amount of antigenic material;
• contacting the rinsed worms with buffered saline extracting solution for a period of at least 30 minutes to obtain a saline extract antigenic material from said worms;
• centrifuging said saline extract for a period of time sufficient to remove substantially all of the worm bodies and other suspended solid particles from said saline extract, and recovering the supernatant which is at least substantially, completely free from suspended solids;
• eluting the supernatant through a gel partition chromatography column capable of separating high molecular weight components, wherein the eluant is buffered saline solution;
• and,
• recovering the eluted fractions containing the antigenic material.

A method of extracting antigenic material from live adult schistosomes comprising the steps of:

• collecting fresh, living adult schistosomes from an infected host without destroying the schistosomes;
• rinsing the fresh, living adult schistosomes with saline solution to remove only blood and non-worm solids but without removing worm by-products;
• storing the collected adult schistosomes in a saline extracting solution for a period of at least about 30 minutes;
• removing the schistosomes from the saline extracting solution;
• and,
• collecting the remaining solution containing live worm-derived antigenic substance.