X-Gal histology and double immunofluorescence histology analysis in human colonic explants transduced by VSV-G-pseudotyped lentivirus (LV) encoding β-Gal. (A) Histological appearance of transduced human explants after X-Gal staining. X-Gal-positive cells, here stained blue, were found mainly in the LP. (B-F) Double immunofluorescence confocal microscopy of human explants transduced with VSV-G. β-Gal-positive cells expressed CD4, CD45, and CD11c, but not CD8, or cytokeratin. In these photomicrographs, β-Gal is visualized by red fluorescence, each cellular phenotype marker is visualized by green fluorescence, and nuclei are visualized by blue DAPI staining, respectively, and all images display fluorescence overlays: (B) β-Gal and CD45; (C) β-Gal and CD4; (D) β-Gal and CD8; (E) β-Gal and CD11c; and, (F) β-Gal and cytokeratin. Double-positive cells, indicated by the arrowheads, are yellow (EP; epithelial cell, LP; lamina propria cell).