C57BL/6 mouse splenocytes were stained with CD45R (B220) Monoclonal Antibody, APC (Product # 17-0452-82) and 0.25 µg of Rat IgM kappa Isotype Control, PE (Product # 12-4341-82) (left) or 0.25 µg of CD43 Monoclonal Antibody, PE (right). Total viable cells were used for analysis, as determined by 7-AAD (Product # 00-6993-50).