Interactions of ACTH and TGF beta on monocyte proliferation: implications for trauma and burn patients

The purpose of this study was to try to elucidate a possible biobehavioral mechanism associated with decreased immune function in trauma patients by determining whether there is an interaction between the effects of ACTH, a stress hormone, and TGF beta, a cytokine, on peripheral blood lymphocyte proliferation. Peripheral mononuclear lymphocytes (PMLs) from healthy donors were preincubated with varying concentrations of ACTH for 24 hr, stimulated with concanavalin A and increasing concentrations of TGF beta, and incubated for 72 hr. Proliferation was assayed by tritiated thymidine incorporation. A parallel aliquot of PMLs were incubated in the presence of ACTH to determine the direct effect of ACTH on mononuclear cell TGF beta production. While harvested supernatant from cells incubated in the presence of ACTH did not contain any detectable TGF beta, ACTH as well as TGF beta were found to significantly decrease cellular proliferation independent of one another. An even greater decrease in cellular proliferation was found when both ACTH and TGF beta were used, compared to either ACTH or TGF beta alone. These results suggest a biobehavioral interaction between ACTH and TGF beta at the cellular level and that interactions to relieve stress may assist in improving function and recovery from trauma.