TABLE 3.

Strain-dependent induction of immune response genes in lungs at 6 h postchallenge with strain 1861 and strain 1 versus resting conditions suggests involvement of the IFN-I response^a

Gene symbol	Strain 1 vs resting		Strain 1861 vs resting
	Fold change	Significance	Fold change	Significance
Crp	1.19	ns	8.20	*
Cxcl10	662.83	**	3,386.31	**
Ifna2	2.64	ns	9.77	*
Ifng	55.52	**	345.61	**
Il10	5.50	*	12.21	***
Irf7	7.29	ns	19.88	**
Mx1	16.97	*	57.60	***
Stat1	1.99	*	6.94	*

^aAnimals (n = 4 per group) were challenged with 10⁷ CFU of strain 1 or strain 1861 or left unchallenged (“resting”). Lungs were harvested for RNA isolation at 6 h postchallenge, and immune response gene expression was analyzed using mouse innate and adaptive immune response RT² Profiler PCR arrays (cutoff used, fold change ≥ 2). Data represent changes in gene expression in lungs from challenged animals relative to resting controls. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ns, not significant (P ≥ 0.05). Italicized values indicate fold changes that do not meet both the cutoff and P value requirements for significance.