GNAT3 and susceptibility to pneumonia measurement: To further investigate the role of bitter taste signaling in S. aureus-induced pneumonia, we established a murine model of S. aureus-induced pneumonia in Gnat3-/- and Gnat3-/–mTas2r104-/-/105-/- mice, which can genetically mutate G protein α subunit (Gnat3) and is thought to eliminate most bitter taste signals (10, 11, 33).