The influence of temperature and season on mitogen-induced proliferation of ground squirrel lymphocytes

Lymphocyte proliferation is a prerequisite for most aspects of the mammalia n acquired immune response. Splenic lymphocytes from golden-mantled ground squirrels collected at different phases of hibernation were stimulated in v itro with several mitogens to measure proliferative ability at several temp eratures. No differences were seen in lymphocyte proliferation at any of th e temperatures tested between animals at different stages of hibernation. N o proliferation was detected at 5 degreesC. T cell mitogens induced signifi cantly higher proliferation at 37 degreesC than at 27 degreesC in lymphocyt es from both summer and hibenrating animals. AB cell mitogen induced simila r proliferation at both 27 degrees and 37 degreesC in cells from summer and hibernating animals. Lymphocyte proliferation appears to be highly tempera ture-dependent in both summer and hibernating animals. Therefore, interbout arousals are essential for the production of a successful acquired immune response during hibernation.