CXCR3⁺ B cells maintain the expression of this receptor during plasma-cell differentiation. (A) Plasma-cell differentiation was induced on isolated B cells as described. Following 8 days of stimulation, between 10% and 40% of B cells had undergone differentiation into CD38⁺⁺/CD20^- plasma cells. (B) Prior to stimulation, cells underwent FACS into CXCR3^- and CXCR3⁺ B cells. At day 3 and day 8 of culture, CD19⁺ B cells and plasma cells were analyzed for the expression of CXCR3 and CXCR4. Upper plots show cultures started with CXCR3^- B cells; lower plots show cultures started with CXCR3⁺ B cells. Shown are results from one representative experiment of five. Percentages indicate the percentage of CD38 and CXCR3 expression in each quadrant gated an CD19⁺ B lymphocytes.