Flies have lung cells that act 'immune-blind' so they don't accidentally attack themselves while they're growing.
March 20, 2026
Original Paper
Tracheal terminal cells of Drosophila are immune privileged to maintain their Foxo-dependent structural plasticity
bioRxiv · 2024.08.22.609264
AI-generated illustration
The Takeaway
While most airway cells react violently to inhaled bacteria, the cells responsible for gas exchange lack the receptors to detect them. This immune privilege is an evolutionary trade-off: if these cells triggered an inflammatory response, they would lose the structural flexibility needed to stretch and grow toward oxygen.
From the abstract
Respiratory organs must balance their primary function of gas exchange with the constant threat of inhaled pathogens. In the Drosophila tracheal system, gas exchange occurs at the tracheal terminal cells (TTCs), the functional equivalents of mammalian alveoli. While bacterial infection triggers a robust innate immune response throughout the broader airway epithelium, we reveal that TTCs are uniquely exempt from this reaction. Mechanistically, TTCs lack expression of the membrane-associated pepti