Antigenicity of structural components from porcine transmissible gastroenteritis virus

Pregnant sows were inoculated with inactivated transmissible gastroenteritis virus and with preparations of virus surface projections and subviral particles derived by detergent treatment of the virus. Neutralising antibody was demonstrated in serum and colostrum from animals that received whole virus or preparations of surface projections whereas subviral particles failed to stimulate neutralising antibody formation. Similar results were obtained with serum from rabbits inoculated with whole virus and structural components. All three preparations stimulated the formation of agglutinating antibodies, as demonstrated by sedimentation analysis and filtration studies with radiolabelled virus. The immunoglobulin classes responsible for neutralising antibody activity in sows inoculated by the intramammary route were examined. In each case where the immunoglobulin class was determined, IgG was found. One sow that received surface projections also had IgA with neutralising activity in her colostrum. In contrast, infection of sows with live whole virus resulted in neutralising antibody of the IgG, IgM and IgA classes.