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The effect of PHA-activated MN-cell supernatants on polymorphonuclear leucocyte function
Abstract:
The effect of PHA-activated mononuclear-cell (MN) supernatants on various polymorphonuclear-leucocyte (PMN) functions were assessed. Treatment of PMN with PHA-activated MN-cell supernatants resulted in greater electrophoretic mobility, indicating an increase in the negative surface charge. PMN directional motility was inhibited in the presence of active supernatants but was not affected by a pulse exposure of the PMN to these supernatants. Neither control nor active supernatants were chemotactic for PMN, but treatment of these cells with active supernatants produced an increase in their phagocytic activity, their ability to reduce NBT and in their glucose oxidation through the hexosemonophosphate shunt. Bactericidal capacity of these PMN was unaltered. Specific loss of leucocyte inhibitory factor (LIF) activity from supernatants of PHA-activated MN cells followed their absorption with PMN cells but not with human MN cells or guinea-pig peritoneal exudate cells. Furthermore, acquired inhibition of migration of the absorbing PMN was observed.
Insights
PHA-activated mononuclear-cell supernatants enhance polymorphonuclear-leucocyte phagocytosis and surface charge but inhibit motility. Leucocyte inhibitory factor (LIF) activity loss suggests PMN interaction is key.
Area of Science:
- Immunology
- Cell Biology
Background:
- Mononuclear-cell (MN) supernatants can modulate polymorphonuclear-leucocyte (PMN) functions.
- Phytohemagglutinin (PHA) activation is a common method to stimulate MN cells.
Purpose of the Study:
- To investigate the effects of PHA-activated MN-cell supernatants on various PMN functions.
- To assess the role of leucocyte inhibitory factor (LIF) in these interactions.
Main Methods:
- Treatment of PMN with PHA-activated MN-cell supernatants.
- Assessment of PMN electrophoretic mobility, directional motility, chemotaxis, phagocytic activity, nitroblue tetrazolium (NBT) reduction, glucose oxidation, and bactericidal capacity.
- Absorption experiments using PMN, human MN cells, and guinea-pig peritoneal exudate cells to determine LIF activity.
Main Results:
- Supernatants increased PMN negative surface charge and phagocytic activity, NBT reduction, and hexosemonophosphate shunt activity.
- PMN directional motility was inhibited by sustained supernatant exposure.
- Leucocyte inhibitory factor (LIF) activity was lost from supernatants after absorption with PMN, indicating specific interaction and acquired inhibition of PMN migration.
Conclusions:
- PHA-activated MN-cell supernatants significantly alter PMN functions, enhancing some and inhibiting others.
- Leucocyte inhibitory factor (LIF) in these supernatants plays a role in modulating PMN migration, with specific interaction involving PMN cells.
