Complement-induced equine neutrophil adhesiveness and aggregation

Area of Science:

• Immunology
• Veterinary Medicine
• Cell Biology

Background:

• Neutrophils play a crucial role in the equine immune response.
• Understanding neutrophil activation is key to managing inflammatory conditions in horses.

Purpose of the Study:

• To investigate the effects of C5a des Arg on equine neutrophils.
• To assess the modulatory impact of anti-inflammatory agents on neutrophil function.

Main Methods:

• Isolation of highly pure equine neutrophils (PMN) using density gradient centrifugation.
• Stimulation of PMN with C5a des Arg derived from zymosan-activated plasma.
• Assays for PMN aggregation, adhesiveness, and ultrastructural changes.
• Evaluation of anti-inflammatory agents (phenylbutazone, dexamethasone).

Main Results:

• C5a des Arg induced rapid equine PMN aggregation, dependent on Mg++.
• Subaggregating doses of C5a des Arg increased PMN adhesiveness.
• Cytochalasin B enhanced aggregation responses.
• Anti-inflammatory drugs inhibited C5a des Arg-induced PMN adhesiveness.
• Ultrastructural analysis showed lamellipodia formation and PMN-PMN contact.

Conclusions:

• Equine neutrophils are responsive to C5a des Arg, exhibiting aggregation and increased adhesiveness.
• C5a des Arg-induced neutrophil responses can be modulated by both steroidal and non-steroidal anti-inflammatory drugs.
• These findings provide insights into equine neutrophil function and potential therapeutic targets.