Figure 5

CD138⁺ plasma cells are localized in close apposition with nerve fibers in the spleen. (A) Plasma cells were detected as syndecan-1⁺ (CD138) cells and the MZ, with an anti-MOMA-1 antibody in spleen sections 6 d after immunization. Most CD138⁺ cells were localized in parafollicular areas in the red pulp (arrows) or less frequently, inside the follicles (arrowhead). (B) Spleen sections stained for synaptophysin, F4/80 and B220. Central artery (ca), subcapsular plexus (scp), splenic cords (sc), follicle (f), trabeculae (arrowhead). (C-D) CD138⁺ cells were localized in close apposition with nerve fibers in perifollicular areas, follicle and surrounding venous sinuses in the red pulp. Images are representative of at least 10 animals. Spleen sections of immunized (E) or nonimmunized (F) animals at d 6 were stained for CD138 and kappa chain. Images are representative of multiple sections from at least four animals and three independent experiments. (G) CD138⁺ or CD138⁻ and CD19⁺ cells were sorted from a B lymphocyte-enriched cell suspension obtained at d 6 after immunization. ELISpot assays were performed on PC-KLH-coated plates.