Application of spin trapping to human phagocytic cells: insight into conditions for formation and limitation of hydroxyl radical.

In recent years spin trapping techniques have been used extensively to better understand the free radical biology of phagocytic cells. These results demonstrate that spin trapping is of adequate sensitivity to detect superoxide and/or hydroxyl radical generated by these cells, and that spin trapping is capable of measuring phagosomal radicals as well. However, neither neutrophils, monocytes, nor monocyte derived macrophages generate hydroxyl radical in the absence of exogenous iron. Furthermore, neutrophil lactoferrin and myeloperoxidase limit the magnitude (and in the case of lactoferrin the duration) of hydroxyl radical formed by neutrophils in an iron catalyzed system. Since monocytic phagocytes possess no lactoferrin, and limited myeloperoxidase, hydroxyl radical may play an important role in the inflammatory behavior of mononuclear phagocytes.