Method establishment for discerned immunogenicity assessment of a recombinant glycoprotein containing nonhuman sialic acid Neu5Gc residues.

Recombinant glycoprotein produced in nonhuman mammalian cell lines can be modified with the immunogenic nonhuman sialic N-glycolylneuraminic acid (Neu5Gc). We describe here a validated method for detection of antidrug antibodies against both protein and Neu5Gc-containing glycan epitopes. An electrochemiluminescent method was established with drug conjugates as capture and detection reagents. Rabbit antidrug polyclonal antibodies were used as the positive control for protein moiety-specific antibodies, while chicken anti-Neu5Gc polyclonal antibodies were used as the positive control for antibodies against Neu5Gc glycan epitope. Specificity to Neu5Gc was verified by signal inhibition with bovine γ-globulin that contains Neu5Gc. The assay illustrated here discerns the immunogenicity of the protein backbone and the sialic acid Neu5Gc glycan moiety of a recombinant protein containing Neu5Gc.