Influence of lymphocytes on the presence and organization of dendritic cell subsets in the spleen

Studies were undertaken to clarify the roles of individual leukocyte popula tions in maintaining the presence and organization of splenic dendritic cel ls (DCs), Using Abs specific for DC subsets, we found that the distinct typ es of DC maintained appropriate compartmentalization within the white pulp of lymphocyte-deficient mice despite an unusual overall distribution of DCs . Even in mice lacking both B and T lymphocytes, the central arteriole rema ined the structure around which T area DCs were organized. Marginal zone ar ea DCs remained in a peripheral sheath excluded from the T area DCs, Additi onally, we revealed an important role for splenic B cells in the presence a nd organization of marginal zone cells, B-deficient or B- and T-deficient m ice lacked sialoadhesin(+) marginal zone macrophages and lacked MAdCAM-1 ex pression in marginal zone reticular endothelial cells. Adoptive transfer of B lymphocytes induced MAdCAM-1 expression but failed to recruit marginal z one macrophages. Taken together, our results demonstrate that the arrival, localization, and persistence of DCs in spleen are events not solely depend ent upon signals from the mature B and T cells or marginal zone macrophages , We suggest that specific stromal elements in the vicinity of the central arteriole are primarily responsible for providing directional cues to the D C.