Figure 2.

Injected hLM-521 is deposited into the GBM. Kidneys from (A) P13 mice either uninjected or at 15 minutes after one injection of hLM-521 (1.2 mg/kg), (B) P17 mice either uninjected or injected with PBS or hLM-521 once daily starting at P12 for 5 days, and (C) P37 mice injected with hLM-521 once daily starting at P12 for 6 days were subjected to confocal immunofluorescence assays. Antibodies to hLAMA5 (green) and agrin (red) were used with nuclear counterstaining (blue). (A) Lamb2+/+ mice showed mostly mesangial staining for hLAMA5 (magenta arrowheads in middle column) that did not overlap with the GBM marker agrin, and weak GBM staining of hLAMA5 (white arrowheads in middle column); Lamb2−/− mice showed hLAMA5 signals that were more distinct in the GBM than in the mesangial matrix (compare white arrowheads to magenta arrowheads in right column). (B) After five doses of hLM-521, Lamb2−/− mice displayed more robust accumulation of hLM-521 in the GBM compared with Lamb2+/− mice. Uninjected or PBS-injected mice showed no specific LAMA5 signal. Dashed lines demarcate the surface of the kidney. (C) After 20 days of chase, Lamb2−/− mice retained hLM-521 in the GBM, even when the mesangial matrix had expanded (asterisks).