FDA发布的2019版《Bispecific Antibody Development Programs Guidance for Industry》对于双特异性抗体的质量属性有以下描述：双特异性抗体的质量属性，例如抗原特异性；亲和力和on/off速率；亲合力（针对靶向同一细胞上两个分子的双特异性抗体）；效力与过程相关的杂质：聚集体，片段，同聚物；稳定性；半衰期可能会影响药理作用，应加以研究。
图1 Immobilized Human CD3E&CD3D Heterodimer Protein, His Tag&Tag Free (Cat. No. CDD-H52W1) at 2 μg/mL, add increasing concentrations of Bispecific T cell Engager (CD3 X BCMA) and then add Biotinylated BCMA Fc,Avitag (Cat. No. BC7-H82F0) at 0.2 μg/mL. Detection was performed using HRP-conjugated streptavidin with sensitivity of 4 ng/mL.
图3 Immobilized Human OX40 Protein, His Tag (MALS verified) (Cat. No. OX0-H5224) at 2 μg/mL, add increasing concentrations of CTLA-4 x OX40 bispecific antibody in 50% Human serum and then add Biotinylated Human CTLA-4, Fc,Avitag (Cat. No. CT4-H82F3) at 0.2 μg/mL. Detection was performed using HRP-conjugated streptavidin with sensitivity of 4 ng/mL (Intact assay)
图5 Comparison of amino acid differences between BsAb1 and BsAb2. Exchanged amino acids are shown in red. Glycans are removed for simplicity. Hinge region cleavage and reduction of BsAbs leading to six different subunits. B) IdeS digestion and reduction of BsAb1. C) SpeB cleavage and reduction of BsAb2. Red stripes in the Fc indicate LALA PG mutation.
