| Abstract: | In earlier studies we investigated the in vivo effects of lipopolysaccharide (LPS) on lymphoid and non-lymphoid cells in the mouse spleen. In order to find out whether LPS localizes in and/or on cells that are affected by this compound, the aim of the present study was to investigate the localization of intravenously injected LPS in the mouse spleen using an immunoperoxidase technique. At different time points after injection, the localization of LPS is demonstrated and LPS-containing cells are characterized. Most of the injected LPS has been taken up by marginal zone macrophages at 2 h after its administration whereas macrophages in the red pulp and at the periphery of the white pulp (marginal metallophils) have ingested less LPS. In the periarteriolar lymphocyte sheath, LPS is concentrated in a large number of acid phosphatase-negative, Ia-positive, large branched cells which were suggested to represent interdigitating cells. Moreover an extracellular dendritic localization pattern of LPS is demonstrated in the corona and central parts of the follicles at different time intervals after its injection. The significance of the localization pattern of LPS in the mouse spleen is discussed. |
