CCR5 down-regulation in EGFP-expressing human monocyte/macrophage population in multiple lymphoid organs. (A) Normalized mean CCR5 expression was compared in EGFP⁺ and mCherry⁺ human CD14⁺/CD33⁺ monocyte/macrophage population in multiple tissues. Bar represents mean value. Samples were analyzed between 14 and 20 weeks after intravenous CD34⁺ cell injection. Aggregate difference, comparing CCR5 expression in EGFP⁺ versus mCherry⁺ cells in all tissues, was statistically significant by Student t test (P < .001). (B) Gating strategies are the same as shown in Figure 5B except for the use of CD14 and CD33 markers. (C) Representative data showing CCR5 expression in CD14⁺/CD33⁺ monocyte/macrophage population.