The Binding Activity of Human CD20 with Anti-CD20 recombinant Antibody. Activity: Measured by its binding ability in a functional ELISA. Immobilized Human CD20 (CSB-MP01<sub>50</sub>07HU) at 2 μg/mL can bind Anti-CD20 recombinant antibody, the EC<sub>50</sub> is 3.243-7.085 ng/mL.