Transgenic Chicken Produces Antibodies with Long CDR3 Regions

Researchers at Crystal Bioscience Inc. have developed a transgenic chicken that produces antibodies with long CDR3 regions, a significant breakthrough in the field of immunology. The chicken's genome has been engineered to include functional immunoglobulin heavy chain genes, which encode for antibodies with long CDR3 regions. This innovation has the potential to create antibodies with improved binding properties, making them useful for various medical applications. The researchers have filed a patent (U.S. Patent Number 12428471) for their discovery, which was published online on September 30, 2025.

Key Takeaways:

• The transgenic chicken produces antibodies with diversified CDR3 regions in the range of 30-67 amino acids in length and comprising 4-10 cysteine residues.
• The chicken's genome has been engineered to include functional immunoglobulin heavy chain genes that encode for antibodies with long CDR3 regions.
• The discovery has the potential to create antibodies with improved binding properties, making them useful for various medical applications.
• The researchers have filed a patent for their discovery, which includes 10 claims, including the development of a method for isolating antibodies from the transgenic chicken.
• One of the claims includes the development of a transgenic chicken whose genome comprises an endogenous immunoglobulin heavy chain locus with a functional immunoglobulin heavy chain gene and a plurality of pseudogenes that donate nucleotide sequence to the nucleic acid encoding the heavy chain variable domain by gene conversion.
• Another claim includes the development of a B cell isolated from the transgenic chicken that produces an antibody with a diversified heavy chain CDR3 region in the range of 30-67 amino acids in length and comprising 4-10 cysteine residues.

Statistics:

• The transgenic chicken's antibodies have a CDR3 region length range of 30-67 amino acids.
• The CDR3 region comprises 4-10 cysteine residues.
• The patent (U.S. Patent Number 12428471) was filed on June 5, 2019, and published online on September 30, 2025.
• The patent includes 10 claims, including the development of a method for isolating antibodies from the transgenic chicken.
• The researchers have engineered the chicken's genome to include functional immunoglobulin heavy chain genes that encode for antibodies with long CDR3 regions.
• The discovery has the potential to create antibodies with improved binding properties, making them useful for various medical applications.

Sources:

• Harriman, William Don. Transgenic chicken that makes antibodies with long CDR-H3S stabilized by multiple disulfide bridges and diversified by gene conversion. U.S. Patent Number 12428471, filed June 5, 2019, and published online on September 30, 2025.
• Crystal Bioscience Inc.