Figure 1. The ML ratio differs significantly in four different inbred mouse strains.

A Gating strategy for flow cytometric analysis. Cells from naïve animals were fixed, stained and data acquired as described in Materials and Methods. Cell debris was gated out by use of a FSC-SSC gate, followed by gating on single cells (FSC-H and FSC-W). A sequential gating strategy was then applied to determine the frequency of T cells (CD3 ⁺), B cells (B220 ⁺), neutrophils (CD11b ⁺ Ly6G ⁺), monocytes/macrophages (CD11b+ CD11c ^low-int, red gate) and CD11b ^int CD11c ⁺ cells (blue gate) as a percentage of single cells. Plots shown are from a sample of a C57Bl/6 spleen. B– D The ML ratio was calculated by dividing the percentage of monocytes/macrophages by the sum of the percentages of B and T cells. ML ratio was analysed in blood ( B), lung ( C) and spleen ( D) of four different mouse strains. E Percentage of CD11b ^int CD11c ⁺ cells in the lung of four different mouse strains, likely to be enriched in alveolar macrophages. Each symbol represents one animal; box plots represent the median (middle line), 25 ^th to 75 ^th percentile (box) and minimum to maximum value (error bars). Data sets are presented in order of decreasing protection. p values were determined using ordinary ANOVA with Holm-Sidak test for multiple comparisons. Multiplicity adjusted p values are reported. A p value <0.05 was considered statistically significant.