DCs express an altered costimulatory phenotype in lupus diseased mice. (a) To study DCs, we analyzed the total population of splenocytes in mice 6 to 9 months old and gated for CD11c+ cells that were negative for the B-cell marker CD19. (b) DCs from mice with lupus (thick dark histograms) express lower levels of CD80, normal levels of CD86, and higher levels of CD40 than DCs of non-autoimmune mice (grey filled histograms). The highlighted numbers are the percentages of DCs positive for the indicated markers and are representative of several mice analyzed and shown in (c-e). The vertical line delineates the threshold of positivity, set on the isotype control background less than 1% (dotted histograms). (c-e) Positivity for CD80 (c), CD86 (d), and CD40 (e) in DCs gated as in (a). Each circle represents the percentage of positive cells in one individual mouse, and the horizontal bars represent the average of each group. (f,g) Averages and standard deviations of CD40 mean fluorescence intensity for expression in DCs from mice 6 to 9 months old of the indicated strains. We analyzed four to nine mice per group in (f) and seven to nine mice per group in (g). 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.