ANTIGENIC RELATIONSHIPS OF ISOLATES OF BORDETELLA-BRONCHISEPTICA FROMSWINE WITH ATROPHIC RHINITIS

The antigenic relationships of twenty Bordetella bronchiseptica isolat es recovered from pigs with atrophic rhinitis were studied using a qua ntitative scroagglutination test. Sera against each isolate were produ ced in rabbits and their titers determined using homologous and hetero logous antigens. Titers of twelve sem that cross-reacted were also det ermined after absorption with heterologous isolates. Antigenic relatio nships were estimated using cross-reactivity indices. Two isolates sho wed marked cross-reactivity with sixteen of the other isolates whereas one cross-reacted with none. It was concluded that B. bronchiseptica recovered from swine is not antigenically homogeneous. The relevance o f these observations to epidemiological and immunoprophylactic studies is discussed.