Selection of a human anti-RhD monoclonal antibody for therapeutic use: Impact of IgG glycosylation on activating and inhibitory FcγR functions

The substitution of plasmatic anti-RhD polyclonal antibodies by a monoclonal antibody (mAb) for preventing the hemolytic disease of the newborn (HDN) is an important issue due to supply and safety concerns. Since it has been suggested that FcγR are involved in the prevention of HDN, the in vitro functional properties of two anti-RhD mAbs differing through their glycosylation profiles were compared using FcγR-based assays to select a candidate mAb. T125(YB2/0), a low fucosylated antibody, bound strongly to both activating FcγRIII and inhibitory FcγRII, as opposed to its highly fucosylated counterpart. It also exerted a strong ADCC against RhD+ RBCs and a potent FcγRIIB-mediated inhibition of cytokine release. Moreover, an in vivo RhD+ red blood cells (RBCs) clearance assay showed that this antibody exhibits a RhD+ RBCs clearance as potent as polyclonal anti-RhD antibodies in NOD-SCID mice. Thus, T125(YB2/O) has been selected to be tested for the prevention of anti-RhD allo-immunization.