Biomedical subjects

K Todd Keylock

Publications and source records attributed to K Todd Keylock.

3 recordsLinked to original sources

PubMed2006

Higher antibody, but not cell-mediated, responses to vaccination in high physically fit elderly.

The purpose of this study was to examine whether cardiovascular fitness, independent of confounding factors, was associated with immune responsiveness to clinically relevant challenges in older adults (60-76 yr). Thirteen sedentary, low-fit (LF; maximal O(2) uptake = 21.1 +/- 1.1 ml.kg(-1).min(-1)) and 13 physically active, high-fit (HF; maximal O(2) uptake = 46.8 +/- 3.4 ml.kg(-1).min(-1)) older adults participated in this study. Dietary intake was assessed, and a battery of psychosocial tests was administered. In vivo antibody and ex vivo proliferative and cytokine responses to influenza (Fluzone) and tetanus toxoid (TT) vaccination and delayed-type hypersensitivity skin tests were performed. HF elderly individuals displayed a higher antibody response to two of the three strains included in the Fluzone vaccine as measured by hemagluttination inhibition, but there was no difference between groups in influenza-specific ex vivo proliferation or IFN-gamma or IL-10 production. HF elderly individuals exhibited a lower IgG(1) response and a tendency for a higher IgG(2) response to the TT vaccine. There were, however, no differences in TT-specific ex vivo proliferation or IFN-gamma or IL-10 production. In contrast, HF subjects had higher proliferative responses to phytohemagluttinin. In addition, there were no differences in delayed-type hypersensitivity responses to fungal antigens between groups. These results suggest that, after accounting for confounding factors, HF elderly individuals have higher antibody responses to Fluzone vaccine and a Th2 skewing of the antibody response to TT. There was little evidence that HF mounted better cell-mediated immune responses to the Fluzone or TT vaccine measured in peripheral blood cells or to other recall antigens in vivo.

Aged↗

PubMed2006

Exercise, inflammation, and innate immunity.

Regular exercise is protective against several chronic diseases ranging from physiologic diseases such as cardiovascular disease to neurologic diseases such as dementia and depression. Exciting recent research points to chronic inflammation as an underlying contributor to many age-related chronic diseases. Cross-sectional and longitudinal studies in animals and humans have shown both an acute and a chronic anti-inflammatory effect. Because innate immunity is a key regulator of inflammatory processes, and chronic inflammation contributes to many illnesses, the effect of regular exercise on innate immunity, most importantly macrophages, holds much promise in terms of defining these mechanisms. Unfortunately, the mechanisms responsible for the observed anti-inflammatory effect of regular exercise have not been elucidated. This article presents several compelling potential mechanisms for the anti-inflammatory effect of exercise, including loss of body fat, reductions in macrophage accumulation in adipose tissue, altered macrophage phenotype in adipose tissue, exercise-induced muscle production of IL-6, or alterations in the balance between the sympathetic and parasympathetic nervous systems. Further investigation to confirm or reject these testable hypotheses will allow better application of exercise therapy to treat and prevent illnesses associated with chronic inflammation.

Animals↗

PubMed2002

Can exercise training improve immune function in the aged?

Many strategies have been used to improve immune function in the aged. Unfortunately, many of these interventions have been disappointing, impractical, costly to develop and administer, or accompanied by adverse side effects. Aside from dietary manipulation (caloric restriction without malnutrition or antioxidant supplementation), research involving behavioral preventative or restorative therapies has been lacking. Moderate exercise training has been shown to elicit beneficial outcomes in both the prevention and rehabilitation of many diseases of the elderly. It has been hypothesized that moderate levels of exercise improves, whereas strenuous exercise or overtraining suppresses, various immune function measures. Three general approaches have been implemented to study the impact of exercise on immune functioning in the elderly: (1) cross-sectional studies, (2) longitudinal studies, and (3) animal studies. In general, cross-sectional studies examining highly active elderly have demonstrated improved in vitro T cell responses to polyclonal stimulation when compared to sedentary elderly. This is corroborated by several animal studies that have shown improved splenic T cell responses in vitro. Unfortunately, human prospective studies have failed to demonstrate consistent improvements in various measures of immune function in older adults. However, it should be cautioned that these studies have included small samples followed over a short duration, measuring a limited number of in vitro immune parameters, with some failing to account for potential confounding influences. Although such findings have the potential to be of substantial public health importance, very few systematic studies have been conducted.

Aging↗