Role of arginase 1 in lung protective immunity against Streptococcus pneumoniae infection in mice

Introduction: Type 2 helper cell (Th2) dominated chronic lung diseases like asthma are characterized by an increased risk for bacterial lung infections. However, the underlying mechanisms are poorly defined. Arginase 1 (Arg1) has been suggested to play an important role in the pathophysiology of asthma, and is rapidly induced in lung macrophages by Th2 cytokines, thereby limiting macrophage-derived antimicrobial nitric oxide (NO) production. Methods: We here examined the effect of Th2 cytokine-induced upregulation or lung myeloid cell-specific conditional knockdown of Arg1 on lung resistance against Streptococcu…