As it turns out, judging by the reaction strength of their immune system to an unknown, but harmless, protein antigen, it's possible for men over 70 to mount an immune response similar to that produced by much younger men -- if they get regular moderate physical activity of about six hours a week.

Previous studies show that the aging immune system suffers from a progressive decrease in function that can lead to several negative situations including increased risk of infectious disease and ineffective response to vaccination. It's been shown that regular moderate cardiovascular exercise such as walking or cycling may offset some of the immune function decline in healthy older people. However most earlier studies tested the effect of exercise on immune function using in vitro measures of immunity, which aren't always predictive of in vivo responses. Furthermore many earlier studies depended on antigenic challenges that weren't novel to the subjects, which stimulated secondary or tertiary responses.

Colorado researchers use KLH for true primary immune response

Researchers at the University of Colorado-Boulder wanted to test the popularly accepted notion that people who maintain a physically active lifestyle will enjoy the benefits a stronger immune system into older age. They designed a novel in vivo challenge to the immune system. To get clean, comprehensive results, they used KLH (keyhole limpet hemocyanin), a benign T cell-dependent protein isolate that has been used extensively with animals in the past, that also is safe for humans.

The study, entitled "Influence of age and physical activity on the primary in vivo antibody and T cell-mediated responses in men," appears in the August 2004 issue of the Journal of Applied Physiology, one of 14 peer-reviewed journ
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Contact: Mayer Resnick
mresnick@the-aps.org
301-634-7209
American Physiological Society
24-Aug-2004