LIBRA HuEasy Monoclonal antibody (mab) humanization service (fully humanized ab)

Chimeric antibody contains variable domains from its original species (example: mouse), and constant regions from another species (example: human being) with high specificity. Compared with the mouse monoclonal antibody, a human-mouse chimeric antibody can efficiently reduce the production of a human anti-murine antibody (HAMA) in clinical trials. However, few patients still have HAMA responses against chimeric antibody, hence the chimeric antibody is not ideal for clinical treatment due to its immunological complication.

For a fully humanized antibody, its genetic source is 100% human-derived, the main ways include three technical routes, one is antibody library screening, creating a large library of variable domains of antibodies (in the form of so-called single-chain Fv fragment, scFv) on the surface of phage and therewith selecting and amplifying in E.coli. The 2nd route is the transgenic mouse, which refers to transferring all human antibody-encoding genes into its genome, which can express human antibodies. The 3rd route is available as an endogenous antibody from the human body. These agents are often harvested by identifying pathogen-specific B cells of patients who have recently recovered from an infection. For instance, Eli Lilly’s monoclonal antibody bamlanivimab (also known as LY-CoV555, aka LY3819253) was originally derived from the blood of one of the first U.S. patients who recovered from COVID-19.

Compared with chimeric antibodies, humanized antibody has lower immunogenicity, wider clinical applications, and higher difficulty in preparation. Even-though, the fully humanized antibody has got a marginal effect in reducing immunogenicity, the cost of production is very expensive.