Chemiluminescence response of phagocytizing human monocytes

Chemiluminescence (CL) occurs as a consequence of phagocytosis of bacteria or inert particles by human polymorphonuclear neutrophils. This phenomenon appears to be related to the production of singlet oxygen and/or electronically excited carbonyl groups which relax with light emission. We report that human monocytes also produce CL after phagocytosis of opsonized bacteria, fungi, or zymosan particles. Monocytes produce approximately one-third of the CL produced by polymorphonuclear neutrophils for all three particles, reflecting possible metabolic differences between cells of these types. Addition of exogenous superoxide dismutase reduced the peak production of CL by 65% for cells of both types, whereas raising the temperature of the cultures from 25 to 37 C approximately doubled the peak CL responses.