Terpenes enhance metabolic activity and alter expression of adhesion molecules (Mac-1 and L-selectin) on human granulocytes.

Granulocytes from healthy blood donors were exposed to terpenes dissolved in ethanol. Flow cytometry was used to measure the expression of the cell surface receptors Mac-1 L-selectin, and CR1, which were detected by monoclonal antibodies. The phagocytic activity was determined by using C3b-coated yeast particles as prey. The metabolic activity was measured by determining the intracellular hydrogen peroxide production using dichlorofluorescein diacetate. After terpene exposure the expression of Mac-1 and CR1 increased (P < 0.001 and P < 0.01, respectively) and the expression of L-selectin decreased (P < 0.001). There was also an increased metabolic activity (P < 0.001). The cell viability, the cell count, and the phagocytic activity remained unchanged. These findings suggest that terpene exposure triggers the granulocytes to a higher degree of activation in terms of an altered expression of the adhesion molecules and an increased metabolic activity.