ULTRAVIOLET-IRRADIATION ACCELERATES APOPTOSIS IN HUMAN POLYMORPHONUCLEAR LEUKOCYTES - PROTECTION BY LPS AND GM-CSF

Polymorphonuclear leukocytes (PMN) play a central role in host respons e to injury and infection, Understanding factors that regulate PMN sur vival may therefore have a major influence on the development of novel treatment strategies for controlling life-threatening infections, as well as local and systemic inflammatory responses, Unfortunately, the presently utilized in vitro culture model of PMN apoptosis makes the e xamination of early biochemical events surrounding PMN apoptosis very difficult, This study demonstrates that a short course of UV irradiati on (15 min) can be used to induce rapid progression of PMN through the apoptotic process with 70-90% of PMN displaying features of apoptosis by 4 h after UV exposure, Bacterial lipopolysaccharide and granulocyt e-macrophage colony-stimulating factor, which are known to prolong PMN survival during in vitro culture, also protected PMN from UV-accelera ted apoptosis, The UV-accelerated model of PMN apoptosis provides anot her valuable tool for the investigation of early signaling pathways as sociated with inducing or delaying PMN apoptosis.