Influence of age and physical activity on the primary in vivo antibody and T cell-mediated responses in men.

In older human populations, both the immunoglobulin (Ig) response and delayed-type hypersensitivity (DTH) to antigenic challenge are altered. As a result, older persons are often inadequately protected from diseases because of ineffective responses to vaccination.

As you may recall, when antigen is presented to the body, the B cell first produces IgM. The B cell then undergoes antibody class switching via T cell help in order to produce IgG. In humans, there are 4 subclasses of IgG, and each differs in its function and cytokine requirement. If IgM production improves with physical activity, it’s possible that there’s improvement in antigen-presenting cell and B cell interaction. On the other hand, if there’s a change in an IgG subclass response, then it might indicate changes in Th1 or Th2 cytokine production.

Through the use of keyhole limpet hemocyanin (KLH), a benign T cell-dependent protein, and 46 active and sedentary, young and older men, this particular study consisted of 2 “sub” studies that (1) sought to verify that KLH immunization in humans would stimulate detectable and antigen-specific antibody and DTH responses, and (2), tested whether there was an age-associated decline in the primary antibody to a novel antigen; an age-associated decline in memory T cell-mediated responses to a skin challenge (DTH) with the antigen; an effect of regular physical activity on these antigen-specific responses; an association of age and physical activity in antigen-specific antibody isotype (IgG and IgM) and subclass (IgG1 and IgG2); and differences in specific antibody response that can be accounted for by total circulating IgM, IgG (1, 2, 3, & 4) in aging and physical activity.

The take-home message from this study, overall, is that physical activity in aging human males is associated with elevated generation of a primary antigen-specific T cell-dependent antibody and DTH responses. In more detail, and taken directly from the literature, the authors observed that there was an age-related decline in the primary antibody response to the novel antigen, KLH; that there was an age-related decline in the memory T cell response to KLH; that older physically active subjects have an improved antibody and DTH response compared with older sedentary subjects that is equal to younger subjects; the changes in anti-KLH IgG production are primarily of the IgG1 subclass; and that the detected changes in antibody are reflective of improvements in antigen-driven responses because total antigen nonspecific Ig was not affected.

Thus, regular physical activity in older males is associated with a stronger immune response to novel antigenic challenge.

Smith, Taro P., Sarah L. Kennedy, and Monika Flshner. Influence of age and physical activity on the primary in vivo antibody and T cell-mediated responses in men. J Appl Physiol 97: 491-498, 2004.