Mouse splenocytes were stimulated for 4 days with F (ab')2 Anti-Mouse IgM, u chain specific and Anti-Mouse CD40 Functional Grade Purifieds (Product # 16-5092-85 and Product # 16-0401-82). Cells were stained with 0.125 µg of Rat IgG2b K Isotype Control PerCP-eFluor® 710 (Product # 46-4031-82) (blue histogram) or 0.125 µg of Anti-Mouse CD252 (OX40 Ligand) PerCP-eFluor® 710 (purple histogram). Total viable cells, as determined by Fixable Viability Dye eFluor® 506 (Product # 65-0866-14), were used for analysis.