The differential effects of bacterial lipopolysaccharide (LPS) on splenic non-lymphoid cells demonstrated by monoclonal antibodies.

In the present study, the effect of LPS on different splenic non-lymphoid cells was investigated. Marginal zone (MZ) macrophages, marginal metallophils and interdigitating cells (IDC) were demonstrated using specific monoclonal antibodies in a two-step immunoperoxidase procedure in combination with enzyme histochemistry. The results indicate that the number of marginal zone macrophages decreases markedly after LPS treatment, but is followed by a rapid repopulation as observed by monoclonal antibody staining and selective uptake of FITC-Ficoll. Marginal metallophils are normally located at the inner border of the marginal sinus and can specifically be identified by the monoclonal antibody MOMA-1. Following LPS stimulation, many MOMA-1-positive cells were present in the corona and central parts of the follicles, with decreasing numbers near the marginal sinus. These findings strongly suggest that LPS induces a migration of marginal metallophils towards the follicle centres. Most of the tangible body macrophages in the follicle centres appeared to be slightly MOMA-1-positive, which indicates that marginal metallophils may, at least under certain circumstances, differentiate into tangible body macrophages. In the inner PALS, many interdigitating cells, NLDC-145-positive cells, can be found. The number of NLDC-145-positive cells was shown to be severely decreased at later time-intervals after LPS administration, resulting in an almost unstained inner PALS at 2 days. In contrast to the above-mentioned splenic non-lymphoid cells, the red pulp macrophages are only minimally affected by LPS.