Potentiation of an IgE-like response to Bordetella bronchiseptica in pigs following Ascaris suum infection.

Ascaris suum-infected and uninfected pigs were vaccinated with Bordetella bronchiseptica bacterin at 8 and 28 days of age. Only the infected pigs gave Type I cutaneous hypersensitivity to the bacterin when tested at 80 days of age. Only the native sera of infected pigs caused passive cutaneous anaphylaxis 24 h after inoculation into guinea pigs. Heating the sera at 56 degrees C for 4 h abolished this property. Mice infected with A. suum for 34 days did not react to the bacterin. An A. suum infection induces an IgE-like response to B. bronchiseptica in pigs that is not explained by cross-reactive antigens. This finding may have practical implications for the immunization against atrophic rhinitis of swine.