Aging and Illness

Kathleen Kelly

As we get older we are susceptible to more illnesses and infections. We don’t respond as intensely to vaccines and as Tortora and Derrickson (2007) say about vaccines, “…they tend to produce more autoantibodies (antibodies against their body’s own molecules).” As we age our immune system doesn’t function as effectively as it did when we were younger. An example of this is that T cells become less responsive to antigens and then fewer T cells respond to infections. (The reason for this is because of decreased production of thymic hormones or an age-related decrease of the thymus). When T cells decrease with age, B cells also become less responsive. Therefore, anti-body levels don’t increase as quickly as they once did in response to a challenge by an antigen, and thus we become more likely to get infections as we get older. One study on this topic said, “Although results vary, many studies confirm that natural killer T cell activity is preserved even among the oldest old. Indeed, some studies have suggested that a decline in natural killer cell activity predicts an increasing risk of serious illness. However, there are some age-related declines in T cell function that affect B cell function, specifically the ability of B cells to help T cells fight infection.”

References:

Tortora, G.J. & Derrickson, B. (2007). Introduction to the Human Body, the Essentials
of Anatomy and Physiology. New York: John Wiley & Sons, Inc.

InfoAging.org. Immune Response and Aging Information Center. Retrieved on June 15,
2009 from http://websites.afar.org/site/PageServer?pagename=IA_b_immune_8_tcell