Modulation of chemokine receptor expression in EBV-transformed B cells in vitro (LCLs) and in vivo (hu/SCID tumors). Flow cytometric analysis for CCR6, CCR7, CXCR3, CXCR4, and CXCR5 expression on B lymphocytes (○), LCL cells (□), and freshly isolated hu/SCID tumor cells (▵). Each point shows the percentage of cells expressing the indicated chemokine receptor. Horizontal bars represent the mean value of each group; the asterisks denote a significant difference compared with B cells (P < .05).