Fig. 6. Expression of the VDR in mature ducts and lymph node of wild-type mice. Formalin fixed sections of mammary glands (A-E) and lymph node (F) from virgin wild-type mice were subjected to immunohistochemistry with a monoclonal antibody directed against VDR. VDR-positive cells appear brown against the blue Hematoxylin counterstain. The number of cells positive for nuclear VDR staining was highest in ducts of mice examined at 5 (A) and 6 (B) weeks of age. Both the number of VDR-positive cells and the intensity of VDR staining declined in mice at 7 (C), 8 (D) and 10 (E) weeks of age. VDR expression was also detected in a subset of lymphocytes within the central lymph node (F), but this did not change with age. Scale bars: 50 µm.