FPR2 and susceptibility to pneumonia measurement: In the meningitis model (caused by S. suis and S. pneumoniae infections) and pneumonia (caused by S. pneumoniae infections), Fpr2 deletion increased the infiltration of neutrophils in CNS and lung, however, the infiltrating neutrophils were in an “inflamed” but “incompetent” state, resulting in a higher fatality rate (24, 25, 28).