Relationship between cold tolerance and generation of suppressor macrophages during acute cold stress

Kizaki, Takako, Tomomi Ookawara, Tetsuya Izawa, JunichiNagasawa, Shukoh Haga, Zsolt Radák, and Hideki Ohno.Relationship between cold tolerance and generation of suppressormacrophages during acute cold stress. J. Appl.Physiol. 83(4): 1116-1122, 1997.Acute coldstress induces suppressor macrophages expressing large numbers ofreceptors to the crystallizable fragment (Fc) portion ofimmunoglobulin G(MAC-1⁺FcRII/III^brightcells), resulting in the immunosuppression of splenocyte mitogenesis. The generation ofMAC-1⁺FcRII/III^brightcells is mediated by the action of glucocorticoids (GCs) through theGC-receptor. In the present study, the generation ofMAC-1⁺FcRII/III^brightcells in peritoneal exudate cells was closely related to the decreaseof rectal temperature during 3-day exposure to 5°C. We nextinvestigated the effects of improved cold tolerance on the generationofMAC-1⁺FcRII/III^brightcells during acute cold stress. Mice were adapted to cold by exposureto 5°C for 3 wk (cold-acclimated mice) and then reexposed to5°C for 3 h (acute cold stress) after living at 25°C for 24 h.The rectal temperature of cold-acclimated mice was not decreased by theacute cold stress. In addition, the proportion ofMAC-1⁺FcRII/III^brightcells in peritoneal exudate cell population from cold-acclimated micewas unaffected by the acute cold stress. The cold acclimation significantly attenuated the increases in serum corticosterone levelsand the expression of the GC-receptor mRNA on peritoneal exudate cellsin response to acute cold stress. These results suggest that thealtered GC response to acute cold stress by the improvement of coldtolerance inhibits the generation of suppressor macrophages duringacute cold stress.