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dc.contributor.authorFletcher, DK
dc.contributor.authorBishop, NC
dc.date.accessioned2011-12-13T19:36:50Z
dc.date.accessioned2011-12-13T19:43:09Z
dc.date.accessioned2011-12-13T19:43:28Z
dc.date.available2011-12-13T19:36:50Z
dc.date.available2011-12-13T19:43:09Z
dc.date.available2011-12-13T19:43:28Z
dc.date.copyright2011-04
dc.date.issued2011-12-14
dc.identifier.citationInt J Sport Nutr Exerc Metab, vol.21(2), pp.155 - 165
dc.identifier.issn1526-484X
dc.identifier.urihttp://hdl.handle.net/10292/3086
dc.description.abstractThis study investigated the effect of a high and low dose of caffeine on antigen-stimulated natural killer (NK) cell (CD3- CD56+) activation after prolonged, strenuous cycling, as assessed by the early-activation molecule CD69. In a randomized crossover design, 12 healthy male endurance-trained cyclists cycled for 90 min at 70% VO2peak 60 min after ingesting either 0 (PLA), 2 (2CAF), or 6 (6CAF) mg/kg body mass of caffeine. Whole blood was stimulated with Pediacel (5 in 1) vaccine. A high dose of caffeine (6CAF) increased the number of CD3-CD56+ cells in the circulation immediately postexercise compared with PLA (p < .05). For both 2CAF and 6CAF, the geometric mean fluorescence intensity (GMFI) of CD69+ expression on unstimulated CD3-CD56+ cells was significantly higher than with PLA (both p < .05). When cells were stimulated with antigen, the GMFI of CD69 expression remained significantly higher with 2CAF than with PLA 1 hr postexercise (p < .05). Although not achieving statistical significance, 6CAF also followed a similar trend when stimulated (p = .09). There were no differences in GMFI of CD69 expression between 2CAF and 6CAF. These results suggest that a high (6 mg/kg) dose of caffeine was associated with the recruitment of NK cells into the circulation and that both a high and low (2 mg/kg) dose of caffeine increased unstimulated and antigen-stimulated NK-cell activation 1 hr after high-intensity exercise. Furthermore, there does not appear to be a dose-dependent effect of caffeine on NK-cell activation 1 hr after prolonged intensive cycling.
dc.languageeng
dc.publisherHuman Kinetics
dc.relation.replaceshttp://hdl.handle.net/10292/3084
dc.relation.replaces10292/3084
dc.relation.replaceshttp://hdl.handle.net/10292/3085
dc.relation.replaces10292/3085
dc.relation.urihttp://journals.humankinetics.com/ijsnem-back-issues/ijsnem-volume-21-issue-2-april-/effect-of-a-high-and-low-dose-of-caffeine-on-antigen-stimulated-activation-of-human-natural-killer-cells-after-prolonged-cycling
dc.rightsInternational Journal of Sport Nutrition and Exercise Metabolism, 2011, 155-165. © 2011 Human Kinetics, Inc. You need permission to use material you have written for Human Kinetics. We require that you inform us of your plans to use your material elsewhere. There is usually no problem in granting the request and the fee is generally waived. However, we may deny a request to use substantial portions of your HK work in a competing work for another publisher. Refer to your contract for details or contact HK’s Proprietary Rights Manager at permissions@hkusa.com.
dc.subjectAdministration, Oral; Antigens, CD; Antigens, Differentiation, T-Lymphocyte; Bicycling; Caffeine; Central Nervous System Stimulants; Cross-Over Studies; Humans; Killer Cells, Natural; Lectins, C-Type; Lymphocyte Activation; Male; Oxygen Consumption; Young Adult
dc.titleEffect of a high and low dose of caffeine on antigen-stimulated activation of human natural killer cells after prolonged cycling
dc.typeJournal Article
dc.rights.accessrightsOpenAccess


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