A SALMONELLA ORAL VECTOR AS VACCINE CANDIDATE FOR POULTRY

THE IMMUNOLOGICAL CONTROL OF VARIOUS DISEASES OF COMMERCIAL CHICKENS HAS BEEN ESSENTIAL TO THE ECONOMIC VIABILITY OF THEINDUSTRY. COCCIDIOSIS IS A GASTROINTESTINAL PROTOZOAL DISEASE OF CHICKENS WHICH IS ESTIMATED TO RESULT IN ANNUAL ECONOMIC LOSSES TO THE INDUSTRY OF $300 MILLION. BECAUSE NO WIDELY ACCEPTED VACCINE IS AVAILABLE, THE INDUSTRY HAS BEEN FORCED TO RELY ON COCCIDIOSTAT DRUGS WHICHHAVE HISTORICALLY HAD LIMITED PERIODS OF EFFICACY. AS A RESULT, ADVANCED TECHNIQUES OF BIOTECHNOLOGY ARE BEING USED BY VARIOUS GROUPS TO IDENTIFY IMMUNODOMINANT COCCIDIAL PROTEINS AND THEIR ENCODING GENES IN EFFORTS TO DEVELOP VACCINES. THE STUDIES WILL CLASSIFY VARIOUS STRAINS OF SALMONELLA, ATTENUATED AS A RESULT OF AROA DELETION MUTATIONS, ACCORDINGTO THEIR TISSUE INVASIVENESS, INTESTINAL COLONIZING ABILITY,AND IMMUNOGENIC POTENTIAL. THE FEASIBILITY OF USING ONE OR MORE OF THESE STRAINS AS AN ORAL DELIVERY SYSTEM FOR FOREIGN ANTIGENS WILL BE ASSESSED USING AS A MODEL FOREIGN ANTIGEN THE NON-TOXIC BINDING SUBUNIT OF THE HEAT LABILE ENTEROTOXIN OF E. COLI. AN IMPORTANT GOAL OF PHASE II RESEARCH WILL BE THE DEVELOPMENT OF AN ORAL VACCINE FOR COCCIDIOSIS USING THE ATTENUATED SALMONELLA IDENTIFIED IN THESE STUDIES TO DELIVER KEY COCCIDIAL ANTIGENS.