B cells from lupus-prone mice express normal levels of CD40. Percentages of B cells positive for CD40 from mice 6 to 9 months old (a) and 6 to 8 weeks old (b) are shown. B cells were gated as B220/CD19-positive and CD11c-negative cells. Results of the Kruskal-Wallis test analyses are shown in the graphs (k-w) and the post hoc Mann-Whitney test analyses are shown below the graphs. N.S. indicates p > 0.05.