Thirty days after a single injection of 1 × 10⁷ β-glucuronidase–positive macrophages into adult MPS VII mice, -galactosidase levels are significantly decreased in several tissues. A significant decrease is produced by both peritoneal-(A) and progenitor-derived (B) cells. An asterisk (*) indicates a significant (P < .05) decrease in specific activity compared with untreated MPS VII (MPS) mice.