Antigen-induced acute and late-phase responses in primates

Area of Science:

• Immunology
• Pulmonology
• Allergy and Asthma Research

Background:

• Allergic airway inflammation involves complex cellular and molecular responses.
• Understanding the roles of eosinophils and neutrophils in late-phase responses is crucial.
• Primate models offer valuable insights into human respiratory diseases.

Purpose of the Study:

• To investigate the influx of inflammatory cells and granule proteins in bronchoalveolar lavage (BAL) fluid.
• To differentiate responses between single acute and dual (late-phase) bronchoconstriction following antigen inhalation.
• To assess the therapeutic effect of dexamethasone on these inflammatory markers and responses.

Main Methods:

• Analysis of BAL fluid from non-human primates after antigen challenge.
• Quantification of eosinophils, neutrophils, and eosinophil peroxidase (EPO) levels.
• Evaluation of chronic dexamethasone treatment effects on cellular influx and EPO levels.

Main Results:

• Dual responders had higher baseline eosinophils than single responders.
• Late-phase response (LPR) showed decreased eosinophils but increased BAL fluid EPO and neutrophils.
• Dexamethasone reduced eosinophils and EPO, and blocked the LPR, neutrophil influx, and EPO increase.

Conclusions:

• Eosinophil activation and significant neutrophil influx are linked to antigen-induced LPR in this primate model.
• Dexamethasone effectively mitigates key inflammatory components of the late-phase airway response.
• These findings highlight the critical role of neutrophils in late-phase allergic airway obstruction.