FIG 6.

Analysis of the nasal associated lymphoid tissue (NALT). The skull was sectioned, allowing staining of the NALT with H&E. (A) Representative 20× images of the NALT. Arrows indicate the NALT. (B) ImageJ analysis of the area of both left and right NALT. The dotted line represents the average area of the NALT in the mock-challenged group. Results are shown as means ± the SEM (n = 4). P values were determined by two-way ANOVA (*, P < 0.05; ***, P < 0.001; ****, P < 0.0001 [compared to the mock-challenge group]).