Affinity Maturation is the process to increase antibody affinity, avidity and stability for an antigen through multiple rounds
of somatic hypermutation and selection in the germinal center in vivo. In the laboratory, scientists apply Affinity Maturation
to lead antibodies generated from the antibody library by introducing mutations and selections with phage display technology in vitro.
Y-Biologics offers tailored Affinity Maturation service using diverse methods such as Light chain shuffling,
Structure-based mutation and CDR hot spot mutation. We apply these techniques alone or together after consulting
with a client to maximize the chance of success.
High Affinity
This approach maintains the heavy chain of a parental antibody.
We insert the amplified heavy chain to a light chain pool which has 106~107 diversity.
As we construct the library for Light chain shuffling and perform biopanning followed by a selection of positive clones against the target.
We analyze and predict CDR residues in the heavy chain which are presumed to be important binding sites with the targets.
We introduce random mutations by substituting those residues with our proprietary antibody library to increase the affinity and construct the library for biopanning with phage display technology.
Structure-based mutation
CDR hotspot mutation
Great Diversity of Light Chain Pool
Successful example
KD (M)
Koff (1/Ms)
IgG Reformatting & Production
Antibody Humanization is a process of replacing non-human antibody frameworks and CDRs with human ones.
Antibodies derived from non-human species cause several immune responses, so they should be designed to be safe in the human body for the development of therapeutic purposes. The aim of this process is for eliminating xenogeneic residues but should not be related to the target recognition.
CDRs are directly related to binding with antigens and framework regions are involved with the structural features. As specifically describe, the binding ability against antigens is determined by SDR (Specificity Determining Residue) in CDR. SDR is usually located in CDR2 & CDR3 of VH and CDR1 & CDR3 of VL. Therefore, when performing CDR grafting as Antibody Humanization, most of companies construct a humanized antibody by grafting mouse CDRs of VH and VL to the human antibody which has similar homology with the mouse antibody.
On the other hand, Y-Biologics performs Antibody Humanization by grafting mouse CDRs to the proprietary fully human antibody library, Ymax®-ABL, and construct libraries for generating humanized antibodies with optimized combination between mouse CDRs and human framework regions.
· Option 1: We substitute all framework regions with the fully human antibody library except for mouse CDRs and then generate humanized antibody by selecting optimized combination.
· Option 2: We further substitute CDR1 in VH and all framework regions with the fully human library.
After construction of the Ymax VL pool library on the mVH, VL which is the optimal partner is selected firstly. Then, the remaining FRs except for the CDRs of mVH are replaced with the Ymax-ABL library. The selected VL and library are prepared to generate the antibody which is humanized both both FRs and VL regions excluding only CDRs of VH.
We perform 3~4 rounds of biopanning against the target after construction of humanized antibody library.
Specific binders are enriched during the biopanning process and this strategy allows us to find humanized antibodies with better physicochemical properties compared with a parental antibody given by the client.
IgG Reformatting & Production
Successful example
Y-Biologics has efficiently humanized a candidate antibody from our immune-focused library and introduce it to be part of a bi-specific antibody. The humanized bispecific antibody is now in the cell line development stage and licensed out to one of the big pharma companies in South Korea. The productivity of the antibody is quite high and stable even in the bispecific format and which validates the quality and stability of our Antibody Humanization technique.
