The in vivo infusion of CD48 MoAb in non-BMT B6 mice shifts the BM and splenic populations toward a CD48^low or CD48^neg phenotype. Non-BMT B6 control mice received irrelevant MoAb or CD48 MoAb (300 μg) on days 0, 3, and 7. On day 9, cells were stained for CD48 expression and then analyzed by FACS. Isotype-matched control MoAb was used to set gates. For BM, CD48 expression was segregated into three antigen density levels. The percent of cells falling within each antigen density level is listed. For spleen, the isotype-matched control MoAb is shown in the thin line and the CD48 MoAb staining in the heavy line. A representative overlay histogram from three individually analyzed mice per group at each time point are shown. The percentages indicate the percent of positive cells in the gate shown. The complete data are tabulated in Table 6.