Lack of mannose receptor affects lymphocyte traffic into the draining lymph nodes but not lymphocyte homing to lymphoid organs from the blood. (A,B) CMFDA-labeled lymphocytes were injected into the footpads of MR^−/− mice and their controls. The input population and lymphocytes from draining the popliteal lymph node were stained with antibodies against CD4, CD8, and B cells, and the percentage of CMFDA-positive CD4, CD8, and B cells was analyzed with a flow cytometer. (A) Representative fluorescence-activated cell sorting (FACS) blots of injected cells (input) and migrated cells recovered from popliteal lymph nodes of one KO and one WT mouse. The blots obtained from a noninjected contralateral lymph node of a WT mouse are shown as a control (control WT). The percentages of CMFDA-positive cells expressing the indicated marker are shown in the boxes. (B) Combined results (mean ± SEM) of all mice analyzed are shown as relative migration index (number of migrated cells in WT mice is 1.0 by definition). (C) Homing of intravenously injected, CMFDA-labeled lymphocytes after 4-hour recirculation time into the indicated organs. The values shown are mean percentages (± SEM) of the homed cells recovered from individual organs. (D) Staining of serial sections with MECA-32 mAb (a pan–vascular endothelial marker against PV-1 antigen), anti-MR mAb, and anti-CD31. Arrows point to some of the blood vessels, which are positive for MECA-32 and CD31 and negative for MR. Thick arrows point to lymphatic sinuses positive for MR and CD31. Staining with a negative control antibody is shown in the insert. Bar represents 50 μm. Objective: Olympus UPlanFl 10×/0.30 Ph1.