The autoimmune theory of aging, introduced by Roy L. Walford in 1969, asserts that with age, the immune system tends to lose efficiency and experiences widespread dysfunction, evidenced by autoimmunity (immune reactions against one's own body proteins) and a decreased ability to respond to infection and other immune challenges. Human immunity is a highly regulated and coordinated process, and is often divided into two components. The first, known as innate immunity, provides a defense against pathogens (potential disease‐causing agents) in a nonspecific way; and the second, known as adaptive or protective immunity, involves a specific response to a pathogen that the body has seen before. Once the body is exposed to an antigen (a foreign substance or pathogen capable of causing an immune response), antibodies will be produced that specifically target that antigen.
There are many different types of cells that are involved in protecting the body against infection; the primary cells involve ...