Antigen challenge increases adherence of circulating neutrophils in horses with chronic obstructive pulmonary disease.

This research involves the study of activation of circulating neutrophils in horses with chronic obstructive pulmonary disease (COPD). It demonstrates that antigen challenge can increase the adherence of these neutrophils, which may enhance their recruitment to the lungs and hence could potentially be a therapeutic target.

Research Context and Aim

• The research is rooted in the observation that activation of circulating neutrophils, a type of white blood cell, comes after challenging horses suffering from chronic obstructive pulmonary disease (COPD).
• In theory, this activation could facilitate the accumulation of these immune cells in the airways, leading to a worsening of the symptoms of COPD.
• The primary aim of this study was to inspect the potential difference in adherence to the protein-coated plastic of blood neutrophils from asymptomatic COPD-susceptible horses and normal horses when they are stimulated by certain mediators.

Methodology and Findings

• A 7-hour antigen challenge was carried out, and twenty-four hours after starting it, the researchers observed that adherence of unstimulated neutrophils from COPD-susceptible horses increased significantly. There were no similar changes in cells from normal horses.
• The researchers used an anti-CD18 monoclonal antibody, H20A, and found that it inhibited the increase in adherence after 24 hours by quite a significant degree.
• Additionally, the percentage of neutrophils in bronchoalveolar lavage fluid at 24 hours increased dramatically as a result of the antigen challenge.

Conclusions and Implications

• The results suggest that antigen challenge results in exposure of circulating equine neutrophils to one or more factors that prime, or activate, these cells.
• This activation can enhance the recruitment of these cells to the lungs, suggesting a potential new approach in the treatment of COPD in horses
• Therefore, inhibiting the activation of circulating neutrophils could possibly serve as a new therapeutic target in the management of equine COPD.