Immunostaining of tissue sections from BM-transplanted GS mice with α-32 and α-GFP antibodies.

Numerous human PPCA-expressing cells were detected by immunostaining with α-32 antibody, monospecific for the human protein (left panels). In the liver of a BMT-treated mouse killed at 9 months after treatment, strong immunostaining was detected in Kupffer cells, as confirmed by staining of adjacent sections with the macrophage-specific anti–Mac-1 antibody. The clear punctate staining of the hepatocytes demonstrated internalization of the corrective enzyme by these cells. In the kidney the presence of the human PPCA was detected in the proximal convoluted tubules and Bowman capsule. Numerous macrophages and splenocytes in the spleen of transplanted mice were positive for the human protein. Staining of the same tissues with α-GFP antibody (right panels) was restricted to cells in locations consistent with their being of hematopoietic origin. Size bar corresponds to 30 μm.