The ability of a subject to respond to antigenic stimulation with the production of antibodies or increased sensitivity to the antigen (hypersensitivity) has been called "immunologic competence". However, the term may be used in a broader sense to describe the relative ability of an animal to establish resistance to a disease process. This concept of immunologic competence not only relates to the responsiveness of the animal to antigenic stimulation but also to other mechanisms of resistance to infectious disease.