Functional and morphological characterization of 4F7+ spleen accessory dendritic cells

Recently we have reported on the production of the mAb 4F7. This recognizes a molecule that Is upregulated on dermal and epidermal dendritic cells after application of contact allergen. Furthermore, this antibody detects an antigen on spleen and lymph node dendritic cells. In this study, we characterize 4F7+ spleen dendritic cells and show that the mAb recognizes In situ few labeled cells in the white pulp of the spleen and approximately 1% of spleen single cell suspensions as evidenced by cell enrichment, immunoperoxldase staining and FACS analysis.Immunohlstologlcal characterization of the cells with mAbs revealed the expression of class II, class I MHC antigens, 33D1, CD11c, ICAM-1, and CD45 molecules. After enrichment and cultivation for -3 days, these cells showed no adherent properties. The capacity of 4F7+ spleen dendritic cells to activate allogeneic T cells in the primary mixed lymphocyte reaction was similar to freshly Isolated la+ Langerhans cells. With regard to the Induction of a prollferatlve response of CD4+ naive T cells that were Incubated with concanavalln A or anti-CD3 mAb, 4F7+ spleen dendritic cells were two to three times more potent than spleen mlcrophages and B cells. Furthermore, 4F7+ cells efficiently stimulated the antigen dependent proliferation of a T helper cell line. The mAb 4F7 will be useful for the purification of dendritic cells and for functional and molecular biological studies.