Induction of pulmonary immunity in cattle by the oral administration of antigen encapsulated in alginate microspheres

Mucosal immunity of the respiratory tract can be induced by the oral administration of antigens. Oral vaccines are easy to administer to a large number of animals. However, the antigens must be protected from the acid and enzymes of the stomach. Encapsulation in polymeric microspheres is one method to protect and enhance delivery of antigens to the inductive immune sites in the small intestine. In this study, ovalbumin was used as a test antigen encapsulated in alginate microspheres. Oral administration of ovalbumin in alginate microspheres resulted in the appearance of IgA-secreting cells in the lungs of calves. The oral administration of vaccines to cattle could be a cost effective way to prevent economically important diseases, such as respiratory infections, in cattle.