Non-lethal complement-membrane attack on human neutrophils: transient cell swelling and metabolic depletion.

The metabolic consequences of non-lethal complement-membrane attack in neutrophils have been investigated by the measurement of cellular ATP content and functional parameters, including chemotactic and phagocytic responses and the capacity to secrete reactive oxygen metabolites, in cells before and after attack. Immediately after non-lethal complement attack, cellular ATP content was reduced by more than 75%, although lactate dehydrogenase content was unaltered. Energy-requiring cell functions were similarly depressed. Incubation of cells in nutrient medium rapidly restored cell-energy stores and functions, demonstrating the completeness of recovery. Fluorescence-activated cell-sorter studies demonstrated that cells undergoing non-lethal complement attack underwent a reversible cell swelling, the cell diameter rapidly increasing from an average of 8.5 micron to 12 micron, then gradually shrinking back to a final average diameter of 8.2 micron. The results indicate that although non-lethal complement-membrane attack causes both metabolic and physical changes in neutrophils, these effects are transient and full functional recovery occurs.