The advent of monoclonal antibody technology has revolutionized the fields of diagnostics, therapeutics, and research. Among the plethora of advancements, chimeric antibody and humanized antibody stand out for their clinical significance and biotechnological innovation. Both types represent efforts to reduce the immunogenicity of murine antibodies and improve their therapeutic efficacy in humans. However, they differ significantly in their structure, production, and applications. Understanding these differences is crucial for researchers, clinicians, and patients alike, navigating the complex landscape of antibody-based therapies.

Chimeric Antibody: Bridging Species with Biotechnology

Chimeric antibody is hybrid molecules engineered by fusing the variable (antigen-binding) domains of a murine antibody with the constant regions of a human antibody. This design typically comprises about 70% human and 30% murine sequences. The creation of chimeric antibodies was a groundbreaking step towards reducing the human immune response against murine antibodies, which was a significant hurdle in the therapeutic use of early monoclonal antibodies.

The process of creating chimeric antibody involves recombinant DNA technology, where the genes encoding the murine variable regions are combined with those encoding human constant regions. This genetic construct is then expressed in mammalian cell lines, producing antibodies that can recognize specific antigens with the murine precision while engaging the human immune system’s effector functions via the human constant region.

Humanized Antibody: A Closer Mimic to Human Immunoglobulins

Humanized antibody take the process of minimizing immunogenicity a step further. They are produced by grafting the complementarity-determining regions (CDRs) — the small, antigen-binding portions — of a murine antibody into a human antibody framework. Essentially, humanized antibody is predominantly human, except for the murine-derived CDRs, making up less than 10% of the murine sequence.

The humanization process involves sophisticated genetic engineering and protein design techniques. It requires the identification of the murine CDRs responsible for antigen binding and their precise insertion into the variable regions of a human antibody framework. This method preserves the antigen specificity of the original murine antibody while significantly reducing its immunogenicity when administered to patients.

Key Differences and Clinical Implications

Immunogenicity: Humanized antibody is generally less immunogenic than chimeric ones because they contain a smaller portion of murine sequences. This reduced immunogenicity translates to a lower risk of adverse immune reactions, making humanized antibody a safer choice for long-term therapy in many cases.

Efficacy and Tolerance: While both chimeric and humanized antibody have shown remarkable efficacy in clinical settings, the closer resemblance of humanized antibody to human immunoglobulins often results in better tolerance and less frequent dosing requirements.

Production Complexity: Humanizing antibody is a more complex and time-consuming process than creating chimeric antibody. It requires detailed knowledge of the antibody structure and function, making it technically challenging and more expensive.

Applications: Chimeric and humanized antibody have wide-ranging applications in treating various diseases, including cancers, autoimmune disorders, and infectious diseases. Rituximab, a chimeric antibody targeting CD20 on B cells, revolutionized the treatment of B-cell lymphomas. On the other hand, humanized antibodies like trastuzumab, targeting the HER2 receptor in breast cancer, have become staples in oncology.


The development of chimeric and humanized antibody represents a pivotal advancement in biotechnology and medicine, offering hope to patients with conditions that were once deemed untreatable. By understanding the differences between these two types of engineered antibodies, researchers and clinicians can better strategize their use in therapy, maximizing efficacy while minimizing adverse reactions. As biotechnological methods advance, the future of antibody therapy looks promising, with the potential for even more refined and effective treatments on the horizon.

KMD Bioscience provides quality assurance for antibody humanization service, including mice, rats, rabbits, etc. Humanization monoclonal antibody refers to the process of tailoring non-human monoclonals to work within human immune systems in an effort to minimize immunogenicity while increasing therapeutic efficacy by including human antibody sequences into existing non-human frameworks. Humanizing monoclonal antibody development typically begins by selecting an existing non-human monoclonal antibody with desirable binding specificity and affinity to serve as its starting point for humanization.