The effect of macrophages posttrauma on T cell functions

OBJECTIVE: To study molecular mechanism of suppressive effect of macrophages posttrauma on T cell functions. METHODS: A murine closed trauma model was used, macrophages were harvested from the abdominal cavity and added into the culture system of T cells, which were separated from splenocytes in normal mice using nylon column. T cell functions and intracellular messenger molecules were determined. In addition, the effect of macrophages' removal from splenocytes of traumatized mice on T cell functions and intracellular messenger molecules was investigated. RESULTS: Macrophages posttrauma in vitro could obviously suppress ConA stimulated normal T cell functions such as T lymphocyte transformation, interleukin 2 (IL-2) production, IL-2 receptor alpha (IL-2Ralpha) expression, IL-2 mRNA and IL-2Ralpha mRNA levels, and elevate cAMP contents of activated normal T cells while decreasing cGMP contents, intracellular free calcium ([Ca(2+)]i) concentration and protein kinase C (PKC) activity. Removal of macrophages from splenocytes of traumatized mice could at certain degree reverse the suppression of T cell functions, decrease cAMP contents while increasing cGMP contents, [Ca(2+)]i concentration and PKC activity. CONCLUSIONS: Macrophages posttrauma may suppress T cell functions via altering messenger molecule levels in activated T cells.