The effect of oxidant injury on the lymphocyte membrane and functions.

We have studied the effect of oxidant stress on the lymphocyte membrane and lymphocyte functions. Lymphocyte cultures were incubated with xanthine oxidase and xanthine, an enzyme system known to generate several highly reactive oxygen compounds. We demonstrated that these lymphocytes were viable after exposure to an in vitro oxidant stress. However, there was a marked reduction in their ability to bind SRBCs and to form caps after Con A stimulation. These lymphocytes also demonstrated a delay in PHA-induced LBT, with maximal response occurring at 5 days instead of 3 days. Catalase, a hydrogen peroxide scavenger, protected lymphocytes from this injury, implicating hydrogen peroxide as the causative agent. Another lymphocyte membrane-related function, the ability to stimulate or respond in MLC, was not impaired after oxidant injury. These results demonstrate that after in vitro oxidant injury, lymphocytes may have alterations in the cell membrane and impaired function.