This result suggests that, before surface saturation, Gx-DiMan surface-bound DC-SIGN molecules do not hinder further binding of other DC-SIGN molecules on the same Gx-DiMan; and Gx-DiMan with a few bound DC-SIGN molecules can still produce the same level of QE as free Gx-DiMan. Therefore, the equilibrium for multiple DC-SIGN molecules binding to one Gx-DiMan can be approximated as multiple copies of one-to-one DC-SIGN-Gx-DiMan binding interactions as Eq.