MZ B cells express active D6. (A) Overlaid CCL2^AF647 uptake histograms of WT (black) and KO (gray) CD19⁺ splenocytes. (B) Dot plot showing fractionation of WT CD19⁺ splenocytes using anti-CD21 and anti-CD23 and overlaid CCL2^AF647 uptake histogram plots from WT (black) and KO (gray) subsets. Bar graph shows the average mean fluorescence intensity (MFI) ± SEM of CCL2^AF647 uptake by each subset. (C) Mean number ± SEM of MZ B cells (CD19⁺CD23^loCD21^hi) per WT and KO spleen (n = 18 per strain). ns indicates not significant (D) D6 mRNA expression by FACS-purified WT splenic FO and MZ B cells. FO cells were set to 1. (E) CCL2^AF647 uptake profiles of D6-deficient (D6^−/−) and CCR2-deficient (CCR2^−/−) CD19⁺ and CD19⁻ splenocytes alongside WT samples prepared in parallel. Boxes highlight cells with specific CCL2^AF647 uptake based on controls performed in the absence of CCL2^AF647. Flow cytometric profiles are representative of data generated from > 3 mice per genotype per experiment, with experiments repeated at least 3 times.