
Incapable of developing a normal immune response, usually as a result of disease, malnutrition, or immunosuppressive therapy.
Having reduced immune responsiveness as a result of inherited defects or infection, particularly by retroviruses and herpesviruses or by administration of immunosuppressive drugs, including antilymphocyte serum, by irradiation, by malnutrition, and by certain disease processes, e.g. cancer.
Having the quality of an immune response that has been weakened by a disease or immunosuppressive agent.