Regular physical activity really does boost immune system in...( als published by the American Physiolog...)

The investigative team was lead by Monika Fleshner and included Taro P. Smith and Sarah L. Kennedy, all from the Department of Integrative Physiology, University of Colorado at Boulder.

Method and results

The researchers tested almost 50 healthy, young (20-35 years of age) and older (60-79) men, some physically active and some sedentary. Using KLH overcame a major problem in many earlier age vs. exercise studies which typically utilized in vitro tests or vaccine or recall antigens to elicit an immune response. In the first stage, all subjects were "immunized" with KLH with blood collected on day one and then each week for a month. The samples were comprehensively tested by ELISA (enzyme-linked immunoabsorbent assay) for anti-KLH IgM, IgG, IgG1 and IgG2.

The second phase was three weeks later. Subjects received an intradermal injection, or skin test, of KLH with inflammation measured each day for five days to assess anti-KLH delayed-type hypersensitivity response (DTH). There was significant reduction in all anti-KLH measures with aging except for anti-KLH IgG2. The physically active older group had significantly higher anti-KLH IgM, IgG, IgG1 and DTH but not IgG2 compared with the sedentary older group.

Experiment one found that the anti-KLH IgM and IgG titers were elevated three weeks after immunization, showing that the ELISA successfully detected KLH-specific Ig and that KLH immunization induced a primary antibody response. Moreover, the KLH skin test resulted in a DTH reaction that peaked after two days, persisting up to five days. Non-immunized subjects had no inflammation, showing that the DTH reaction was specific to KLH recognition.

Discussion and conclusion

The researchers said this was the "first study to clearly demonstrate in humans by use of a novel in vivo antigenic challenge that a physical active lifestyle is associated with
'"/>

Contact: Mayer Resnick
mresnick@the-aps.org
301-634-7209
American Physiological Society
24-Aug-2004