VACCINE FOR INFECTIOUS BURSAL DISEASE VIRUS

THE IMMUNODOMINANT ANTIGEN OF INFECTIOUS BURSAL DISEASE VIRUS HAS BEEN SHOWN TO BE A 32 KD STRUCTURAL PROTEIN. MONOCLONAL ANTIBODY, DIRECTED AGAINST THE PROTEIN, PASSIVELY PROTECTS CHICKS. SYNTRO HAS CLONED THE ENTIRE LARGE GENOMIC RNA SEGMENT WHICH CODES FOR A SINGLE LARGE POLYPROTEIN THAT IS PROTEOLYTICALLY PROCESSED IN VIVO TO YIELD THE 32 KD ANTIGEN AND TWO OTHER PROTEINS. SYNTRO WILL CONSTRUCT AND EXPRESS A NUMBER OF GENE FUSIONS BETWEEN GENES THAT ARE HIGHLY EXPRESSED IN E. COLI AND THAT PORTION OF THE IBDV CLONE THAT CODES FOR THE 32 KD ANTIGEN AND, IN SOME CASES, ADJACENT IBDV SEQUENCES AS WELL. THESE FUSION PRODUCTS WILL BE IDENTIFIED BY ELECTROPHORESIS FOLLOWED BY PROTEIN STAINING AND WESTERN ANALYSIS USING CONVALESCENT CHICKEN SERA CONTAINING PROTECTIVE ANTIBODIES. THOSE FUSIONS WHICH ARE PRODUCED IN LARGE QUANTITIES AND RETAIN STRONG REACTIVITY TO NEUTRALIZING ANTIBODIES WILL BE SELECTED DURING PHASE I AND WILL PROVIDE THE BASIS FOR A PHASE II STUDY DESIGNED TO PRODUCE THESE PROTEINS BY BACTERIAL FERMENTATION AND TO EVALUATE THEIR USEFULNESS AS SUBUNIT VACCINES IN FIELD TRIALS.