Immunofluorescent analysis of CD4 (green) on the surface of D10.G4.1 mouse T-lymphocytes. Formalin fixed cells were blocked with 1% Blocker BSA (Product # 37525) for 15 minutes at room temperature. Cells were probed with a CD4 monoclonal antibody (Product # MA1-146) at a dilution of 1:20 for 1 hour at room temperature, washed with PBS, and incubated with a DyLight 488-conjugated goat anti-rat IgG secondary antibody (Product # SA5-10018). Nuclei (blue) were stained with Hoechst 33342 dye (Product # 62249). Images were taken on a Thermo Scientific ToxInsight Instrument at 20X magnification.