Bronchus-associated macrophages – lung immune cells – identified as local allergen-presenting cells
You begin to sneeze and wheeze. Your chest tightens. You're having an allergic asthma attack. This is caused by inhaling allergens, such as pollen or dander, reaching immune cells called T-helper cells (Th2 cells), triggering inflammation around your airways. However, the mechanism by which these allergens are captured and presented to Th2 cells is unclear. Researchers investigate using mice genetically engineered to have different cells, including immune cells, bearing fluorescent proteins. Mice lungs were imaged with two-photon microscopy (pictured), revealing cells lining the airways (green), collagen outside cells (blue) and other cells (red). Mice inhaled fluorescently-tagged allergens, and subsequent imaging revealed allergens were captured and presented by immune cells in the lungs called bronchus-associated macrophages (BAMs). BAMs accumulated in collagen-rich regions near airway branch points, where inhaled allergens likely deposit, and interacted with Th2 cells and other immune cells called dendritic cells, supporting their role as allergen-presenting cells.
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