Exercise-recruited NK cells display exercise-associated eHSP-70

Peggy Horn*, Amelia Kalz, Chin Leong Lim, David Pyne, Philo Saunders, Laurel Mackinnon, Jonathon Peake, Katsushiko Suzuki

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


It is hypothesized that increased plasma or serum concentrations of extracellular heat shock proteins (eHSP) serve as a danger signal to the innate immune system. Cellular binding of eHSP leads to activation of NK cells and monocytes, as measured by their increased cytokine production, mitotic division and killing capacity. We examined whether eHSP binds to NK lymphocytes in vivo in athletes performing endurance exercise in the heat. Eighteen trained male runners ran at 70% VO 2max at 35 ° C and 40% relative humidity. Venous blood collected before, after and 1.5 h after exercise was analysed for leukocyte distribution, phenotype and eHSP70. NK cell-enriched samples were examined for co-localization of CD94 and eHSP70 expression. Plasma eHSP-70 concentration was measured by ELISA. Subjects ran for ~50 min, which elicited a reversible leukocytosis. NK cell count increased 83% (p < 0.01) immediately after exercise, then decreased to 66% of the resting level 1.5 h after exercise (p < 0.05). Plasma eHSP concentration increased 167% after exercise and remained elevated (by up to 71%) 1.5 h after exercise (p < 0.01). eHSP was expressed on both NK cells and monocytes at all times; the count of NK cells positive for eHSP doubled from 0.04 ± 0.02 10 9/L (mean ± SD) to 0.08 ± 0.06 10 9/L after exercise. In summary, exercise in the heat increased free plasma eHSP concentration, and the eHSP co-localized with CD94 on NK cells. These data confirm the link between exercise and activation of the innate immune system.

Original languageEnglish
Pages (from-to)100-111
Number of pages12
JournalExercise immunology review
Publication statusPublished - 2007 Dec 1


  • Cytokines
  • Exercise
  • HSP
  • Innate immunity
  • Lymphocytes
  • Natural killer cells

ASJC Scopus subject areas

  • Immunology


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