H2O2 RENDERS CELLS ACCESSIBLE TO LYSIS BY EXOGENOUS PHOSPHOLIPASE A(2) - A NOVEL MECHANISM FOR CELL-DAMAGE IN INFLAMMATORY PROCESSES

Phospholipase A(2) (PLA(2)) and H2O2, secreted from activated inflamma tory cells, play a central role in the tissue damage occurring in infl ammatory processes. However, while exogenous PLA(2) alone does not cau se cell lysis, it readily does so when acting with H2O2. We have found that H2O2 degrades cell surface proteoglycans, thus rendering the mem brane PL accessible to hydrolysis by exogenous PLA(2). This novel mech anism introduces a role for cell surface proteoglycans in protection o f cells from damage by pro-inflammatory agents, and may assign a centr al role for the combined action of H2O2 and PLA(2) in inflammatory and bacteriocidal processes.