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What is Immunosenescence and Definition
A decline in immune function and IMMUNE RESPONSE that occurs with aging. Researchers believe immunosenescence accounts for the increase in cancer and infections such as INFLUENZA and PNEUMONIA in people of old age.
The decline occurs in both CELL-MEDIATED IMMUNITY (sometimes called cytotoxic immunity), in which T-cell lymphocytes attack and kill foreign antigens, and humoral immunity, in which B-cell lymphocytes generate the antibodies that circulate in the BLOOD. Though immunosenescence appears a normal physiologic process in that it happens to everyone as they grow older, researchers question whether it is an intrinsic function under genetic regulation or an extrinsic reaction to environmental factors, ranging from EATING HABITS to toxic exposure.