T cell-specific P2RX7 favors lung parenchymal CD4+ T cell accumulation in response to severe lung infections

Abstract

CD4+ Tcells are key components of the immune response during lung infections and can mediate protection against tuberculosis (TB) or influenza. However, CD4+ Tcells can also promote lung pathology during these infections, making it unclear how these cells control such discrepant effects. Using mouse models of hypervirulent TB and influenza, we observe that exaggerated accumulation of parenchymal CD4+ Tcells promotes lung damage. Low numbers of lung CD4+ Tcells, in contrast, are sufficient to protect against hypervirulent TB. In both situations, lung CD4+ Tcell accumulation is mediated by CD4+ Tcell-specific expression of the extracellular ATP (eATP) receptor P2RX7. P2RX7 upregulation in lung CD4+ Tcells promotes expression of the chemokine receptor CXCR3, favoring parenchymal CD4+ Tcell accumulation. Our findings suggest that direct sensing of lung eATP by CD4+ Tcells is critical to induce tissue CD4+ Tcell accumulation and pathology during lung infections.