ISSN: 1745-7580
Ivan NG, Fairchild TJ, Greene WK and Hoyne GF
The study examined the effect of exercise and hypoxia on the mobilization and egress of innate lymphocytes (ILCs) and adaptive T cell populations in the blood. The ILCs have emerged as a critical population of cells in immune regulation at mucosal surfaces in animals and humans. Eleven healthy male subjects performed (i) 45 min of exercise at 50% VO2 peak on a cycle ergometer under normoxia and (ii) hypoxia, or (iii) while resting in hypoxia. Blood samples were obtained pre-exercise, immediately post-exercise and 60 min post-exercise and were analyzed by flow cytometry to examine the type 1 and type 3 ILCs and CD4+ and CD8+ naive and memory cell populations. There was a significant increase in the number of type 1 (NK cells) and type 3 ILC22 cells in the blood in response to exercise under normal oxygen conditions followed by a significant egress of these cells following the cessation of exercise. Exercise performed under hypoxic conditions abrogated the mobilization response of NK cells and ILC22 cells. Type 3 LTi cells were mobilized into the blood only under hypoxic rest conditions. No significant changes were observed when we analysed total CD4+ and CD8+T cell populations or the naive and memory subsets. This study highlights that distinct innate populations are mobilised under different environmental conditions and types of stress.