UNIQUE TISSUE DISTRIBUTION OF A MOUSE MACROPHAGE C-TYPE LECTIN

We examined mouse tissue for the expression of macrophage galactose/N- acetylgalactosamine-specific C-type lectin using a rat monoclonal anti body (mAb) specific for this lectin (mAb LOM-14), The binding of mAb L OM-14 was detected in detergent extracts from tissue by means of immun oblotting analysis, It was shown that this mAb did not cross-react wit h mouse hepatic lectins, a structural homologue, The macrophage lectin was widely distributed among various mouse tissues as judged by the a ffinity isolation followed by the immunochemical detection, The except ions were brain, liver, kidney, small intestine, and peripheral blood, Extracts from these organs exhibited, at best, very weak signals upon mAb LOM-14 binding, despite the presence of cells expressing macropha ge markers, The most intense signal was observed in the extract from s kin, suggesting that cells expressing this lectin are abundant in skin , The tissues shown to contain this lectin were further investigated b y immunohistochemical staining of the sections, Cells were distributed in the connective tissue and in the interstice, particularly the derm is and subcutaneous layer of skin, Cells localized in the epithelium o f skin (epidermis) or other epithelia that we examined were not staine d, Perivascular localization of cells stained with mAb LOM-14 was also demonstrated in cardiac and skeletal muscle tissues, Immunoelectron m icroscopy revealed the presence of this lectin along the rough endopla smic reticulum, In conclusion, the distribution of C-type lectin speci fic for galactose/N-acetylgalactosamine in mice was unique, The connec tive tissue-specific distribution should provide important information on the biological role of this lectin.