When linear regression analysis was used to examine the correlations between the dose of infection, the percentage of P14 cells producing IFN-γ in a bystander manner, and the level of systemic IL-12, statistically significant correlations were observed between I) the CFUs of bacteria recovered from the spleens 24 hrs post infection and the percentage of P14 cells producing IFN-γ; II) the percentage of P14 cells producing IFN-γ and the levels of serum IL-12, and III) the CFUs of bacteria recovered from the spleens 8 and 24 hrs post infection and the levels of serum IL-12 (Fig. 5d). The gene discussed is IFNG; the disease is infection.