Localization of antigen in tissue cells; V. Capsular polysaccharide of Friedländer bacillus, type B, in the mouse.

The fate of the capsular polysaccharide of Friedländer B bacillus in the mouse after its intravenous administration was studied by means of homologous antibody labelled with fluorescein. The results indicate that this acid polysaccharide, like pneumococcal polysaccharide, types II and III, was rapidly taken up by phagocytic cells throughout the body, where it persisted in decreasing concentration for more than 33 days. It was widely distributed in the capillary endothelium and on collagenous fibres in all organs. It made a transient appearance in or on lymphocytes in the spleen and lymph nodes. It was found in the hepatic epithelium and in the bile; in the juxtaglomerular segment of the distal renal tubule and in an occasional cast in the lumens of collecting tubules; in the epithelium of some uterine glands; and in cells in the steroid-secreting tissues of the ovary, suprarenal cortex, and perhaps of the testis. In joints the synovial membranes contained large amounts of antigen, and some also penetrated into cartilage cells adjacent to the joint cavity. Osteoblasts and a few osteocytes also took up the polysaccharide. When administered by inhalation, the polysaccharide was found in high concentration in the pulmonary macrophages but could not be found constantly in other lung elements.