You Don’t Need to Worry About the Shortcomings of Antibody Humanization

Humanized antibodies are antibodies from non-human species whose protein sequences have been modified to increase their similarity to antibody variants produced naturally in humans. Humanization is capable of reducing the immunogenicity of monoclonal antibodies derived from xenogeneic sources as well as improving their activation of the immune system.

Since the development of the hybridomxa technology, a large number of rodent monoclonal antibodies with specificity for antigens of therapeutic interest have been generated and characterized. Rodent antibodies are highly immunogenic in humans, limiting their clinical applications, especially when repeated administration is required. More importantly, they are rapidly removed from circulation and can cause systemic inflammatory effects as well.

These obstacles, however, have stimulated the development of a new technology, antibody immunization. It is not inexplicable at all. Different approaches were carried out or are developing by scientists and researchers so as to overcome these difficulties. Creative Biolabs has announced three related strategies that can preserve the specificity and affinity of the antibody towards the antigen, and significantly or completely eliminate the immunogenicity of the antibody in human body.

CDR Grafting & SDR Grafting

The CDR (complementarity-determining region) grafting platform it established is featured with randomization of a small set of framework residues utilizing phage display technology and computer modeling. Six CDR loops comprising the antigen-binding site are grafted into corresponding human framework regions in this platform. While, simple grafting of the rodent CDRs into human frameworks does not always reconstitute the binding affinity and specificity of the original antibody since framework residues are involved in antigen binding by supporting the conformation of the CDR loops indirectly or contacting the antigen directly. To this problem, Creative Biolasb has developed a computer modeling method to randomize certain framework residues in addition to CDR grafting. Together with the randomized residues, the grafted CDRs are cloned into a phage display library? and the humanized antibodies with the best affinity are selected by screening of the library. This approach enables the epitope specificity of the original antibody to be retained. Despite of that, humanization by this approach is impossible to be 100% by now since the CDR regions are still of a rodent origin.

Chain Shuffling

Creative Biolabs’ chain shuffling strategy is an entirely selective humanization strategy which is based on the construction and screening of two chimeric phage display libraries, with which approach the light chain of the rodent antibody is first replaced by light chains in one of its well-tested human antibody libraries. The hybrid antibody library obtained is then screened by panning against the particular antigen after which the heavy chain of the selected hybrid antibodies is replaced by heavy chains of the human antibody library. Subsequent screening of this secondary chimeric library will produce fully humanized antibodies. As phage display library screening mimics in vivo antibody selection and evolution procedure, chain shuffling can result in this special type of antibody with higher affinities compared with that of the original one. This sequential chain shuffling procedure can generate several versions of them with different sequences.

Humanized IgG library screening

This method enables the selection of antibody under humanization technology in a full-size IgG that retains or increases the original affinity of the mouse antibody. Also, in comparison with the above bacterial phage display based approaches, this mammalian cell surface display approach allows the selection of it with high affinity in a dimeric IgG format. Learn more about humanized IgG library screening. Read more.....

Creative Biolabs is a professional biotech service provider. Since been established in 2005, it has been focused on the research and development of antibody humanization technology. Many achievements have been made in this field during these years. Learn more about Creative Biolabs.