Time course of natural killer cell activity and lymphocyte proliferation in response to two acute stressors in healthy men.

To clarify the time course of immune system activity during and after acute stressor exposure, this study collected immune measures from 31 men at 6 times (before, during, and after 2 common laboratory stressors; mental arithmetic with harassment or a cold pressor task). The 6-min stressor period was associated with increased self-report of pain and distress in both stressor groups and with increased systolic and diastolic blood pressure and heart rate in the mental arithmetic group. Increased natural killer cell activity in this group was observed during the task (2 and 5 min into the task) and 5 min after the task ended. A significant Group x Time effect was observed for lymphocyte proliferation to pokeweed mitogen, and a significant Group x Time x Dilution effect was observed for proliferation to concanavalin A. Inspection of the data suggested that this interaction was due to a reduction in proliferation in both stressor groups during the task period.