Transferred CD35⁺B220⁺ cells are found in splenic white pulp. (A) Isolated CD35⁺B220⁺ cells were labeled with PKH26 and administered intravenously into naive C57BL/6J-Jcl mice (Live; top panels in A and B). As controls, PKH26-labeled CD35⁺B220⁺ cells were fixed with ethanol and intravenously injected into C57BL/6J-Jcl mice (Fixed; bottom panels in A). On day 8 after the adoptive transfer, cryosections of the spleen were examined by immunofluorescence staining with biotin-conjugated anti-B220, anti-CD11b, anti-IgM, and anti-CD35 mAbs or anti-MARCO polyclonal Ab. Streptavidin-conjugated Alexa Fluor 488 or anti-rat IgG conjugated with Alexa Fluor 488 was used to visualize the microarchitecture of the spleen. Samples are representatives of 3 independent experiments. All images were taken and analyzed with a DeltaVision RT system. Photographs of upper rows were taken with a 20×/0.75 NA objective. (B) High-power photographs of the area enclosed by the yellow square in panel A. Yellow bars, 100 μm; blue bars, 20 μm.