Canine IgA and IgA deficiency: Implications for immunization against respiratory pathogens

Immunoglobulin A (IgA) is widely recognized as the important antibody isotype involved in protective responses on mucosal surfaces, where it acts primarily by effectuating immune exclusion of foreign material. Selective IgA deficiency (SIgAD) is the most common immunodeficiency disease in dogs and humans and has consequences for mucosal immunity. This review is a comparative look at the biology of IgA and SIgAD with a focus on how this branch of immunology relates to vaccine selection and efficacy for canine infectious respiratory disease.