THE DEVELOPMENT OF A RECOMBINANT VACCINE FOR ISOSPORA SUIS

ISOSPORA SUIS HAS COST THE SWINE PRODUCER AN ESTIMATED 269 MILLION DOLLARS (IN 1991 DOLLARS), FROM 1980 TO 1988. THE LOSS IN 1991 IS EXPECTED TO BE OVER $20 MILLION, CONSERVATIVELY ESTIMATED, FROM PORCINE COCCIDIOSIS. THERE IS NO CURRENT VACCINE ON THE MARKET, NO COCCIDIOSTATS ARE LICENSED FOR SWINE USE, THE USE OF NON-LICNESED COCCIDIOSTATS ARE NOT EFFECTIVE, AND THE TREATMENT OF PIGS WITH COCCIDIOSTATS IN NOT COST EFFECTIVE. THERE HAS BEEN NO REPORTED METHOD TO PRODUCE THE COMPLETE LIFE CYCLE OF THIS ORGANISM OUTSIDE THE PIG, ALTHOUGH MANY INVESTIGATORS HAVE TRIED. WE PROPOSE TO USE RECOMBINANT TECHNIQUES TO ISOLATE THE IMPORTANT ANTIGENIC PROTEINS FROM THE DESIRED STAGES OF ISOSPORA SUIS THAT WILL LEAD TO PROTECTION OF VACCINATED PIGS WHEN CHALLENGED WITH THIS PATHOGEN. THE TECHNICAL OBJECTIVE OF THIS PHASE I PROPOSAL INCLUDES OBTAINING THE REQUIRED MATERIAL (OOCYSTS, SPOROZOITES, AND MEROZOITES), IDENTIFICATION OF IMPORTANT PROTECTIVE ANTIGENIC PROTEINS, DETERMINATION OF THE IMPORTANCE OF PASSIVE ANTIBODY PROTECTION TO PIGLETS FROM GILTS, AND THE PREPARATION OF CDNA LIBRARIES FROM SPOROZOITES AND MEROZOITES. THE USE OF RECOMBINANT TECHNIQUES RESULTS IN A POWERFUL APPROACH TOWARD THE PRODUCTION OF AN EFFECTIVE VACCINE FOR ISOSPORA SUIS, WHEN USED IN COMBINATION WITH IMMUNOLOGICAL ASSAYS TO CONFIRM PROTECTIVE ANTIGENS.