Distribution of F4/80+ cells in inflammatory foci after infection with thermally preinduced Y. pestis.

a Within each focus size, the percent having each distribution of stained cells is given, and the actual number of foci in each category is in parentheses.b Foci were measured in their largest aspect and classified as small (100 µm).c The presence of stained cells within the central part of the focus identified that lesion as having a Central distribution. Foci with a central distribution of stained cells tended to have F4/80+ cells all over the focus (not just at the center). If the cells were seen only in a ring around the perimeter extending inward not more than 25% of the diameter of the focus, the distribution was designated as Edge.d Data are from two mice per infecting Y. pestis strain, one from each independent experiment. The distributions between small vs. medium + large foci for 17-h infections by the two Y. pestis strains (the two experiments with dose = 106) did not differ significantly by Fisher's exact test. For both parent and ΔyopM-1 Y. pestis in both 106 and 107 doses, the distributions of F4/80+ cells between small vs. medium + large foci were statistically different by Fisher's exact test (p = 0.000 for 2-tailed determination that the odds ratio is significantly different from one, where the odds ratio = No. Small Central/No. Small Edge ÷ No. Medium+Large Central/No. Medium+Large Edge).Distribution of F4/80+ cells in inflammatory foci after infection with thermally preinduced Y. pestis.