抗体ヒト化（Antibody Humanization）

Recombinant antibody technologies have witnessed remarkable advancements and demonstrated significant clinical success. However, a major challenge associated with the use of murine monoclonal antibodies as a therapeutic is their immunogenicity causing a human anti-mouse antibody (HAMA) response. This response occurs when humans react to the foreign protein, causing complications from immune complex formations and resulting in the antibody treatment being ineffective. To tackle this issue, chimeric antibodies were created using genetic engineering techniques, combining human constant domains with mouse variable domains that recognized the human antigen of interest, thus preserving antibody specificity.¹

Antibody humanization was further developed by modifying the mouse antibodies to be more similar to human antibodies by CDR (complementarity determining region) grafting. CDRs of non-human antibodies are grafted to human frameworks of high homology. Typically, some vernier zone residues (murine residues in framework regions) are also retained as they have been shown to affect CDR loop conformation and antibody affinity.^2,3 Ultimately, humanized antibodies carry a lower risk of inducing immune responses in humans than mouse or chimeric antibodies.

The humanization process is as follows:

1. Sequence design and synthesis

2. Plasmid construction and preparation

3. Transient expression

4. Affinity purification

5. Stringent quality control

6. Affinity ranking

Biointron offers an antibody humanization service utilizing the CDR grafting and back mutation platform. Our service offers several advantages, including:

• Guaranteed affinity (comparable to parental antibody / no cost if guaranteed affinity is not reached)

• Fast turnaround time (only 4-5 weeks to obtain humanized antibodies)

• Extensive experience and strong expertise (10+ years in humanized antibody design / we have produced 20,000 antibodies)

References:

1. Mak, T. W., & Saunders, M. E. (2006). Exploiting Antigen–Antibody Interaction. The Immune Response, 147-177. https://doi.org/10.1016/B978-012088451-3.50009-0

2. Yaghoub Safdari, Safar Farajnia, Mohammad Asgharzadeh & Masoumeh Khalili. (2013). Antibody humanization methods – a review and update. Biotechnology and Genetic Engineering Reviews, 29(2), 175-186. https://doi.org/10.1080/02648725.2013.801235

3. Harding, F. A., Stickler, M. M., Razo, J., & DuBridge, R. B. (2010). The immunogenicity of humanized and fully human antibodies: Residual immunogenicity resides in the CDR regions. MAbs, 2(3), 256-265. https://doi.org/10.4161/mabs.2.3.11641