In this study, we carried out host engineering to generate a therapeutic glycoprotein largely devoid of plant-endogenous O-glycans for functional characterization. We generated four variants of a potentSARS-CoV-2 neutralizing antibody, COVA2-15 IgA1. The variants that differed in the number of modified proline residues and O-glycan compositions of their hinge region were assessed regarding their physicochemical properties and functionality.