To concurrently monitor the burden of GAS and host innate immune response in the same mouse, the reporter mice carrying firefly luciferase under transcriptional control of the NF-κB promoter were subcutaneously inoculated in the air pouch at the back site with a lethal dose of A20 carrying a lux operon and monitored using Living Image software at 3, 24, and 48 h post infection (hpi). The gene discussed is NFKB1; the disease is infection.