Distribution of dendritic cells expressing dendritic cell-specific ICAM-3-grabbing non-integrin (DC-SIGN, CD209): Morphological analysis using a novel Photoshop-aided multiple immunohistochemistry technique

The distribution of dendritic cells (DCs) expressing DC-specific ICAM-3-grabbing non-integrin (DC-SIGN, CD209) and the morphological interaction of DC-SIGN(+) DCs with other cells, especially B cells, in tonsillar and other lymphoid tissues were investigated by multiple immunohistochemistry (IHC) using the graphics editing program Photoshop, which enabled staining with 4 or more antibodies in formalin-fixed paraffin sections. Images obtained by repetition of conventional IHC using diaminobenzidine color development in a tissue section were processed on Photoshop for multiple staining. DC-SIGN(+) DCs were present in the area around the lymphoid follicles and formed a DC-SIGN(+) DC-rich area, and these cells contacted not only T cells, fascin(+) DCs, and blood vessels but also several subsets of B cells simultaneously, including nave and memory B cells. DC-SIGN(+) DCs may play an important role in the regulation of the immune response mediated by not only T cells but also B cells. The multiple IHC method introduced in the present study is a simple and useful method for analyzing details of complex structures. Because this method can be applied to routinely processed paraffin sections with conventional IHC with diaminobenzidine, it can be applied to a wide variety of archival specimens.