Our Advantages for Recombinant Rabbit Monoclonal Antibodies

Broader antibody repertoire

Experience in antibody development suggests that the rabbit immune system can produce antibodies that recognize more unique epitopes. Rabbits are known to have a different immune response mechanism than humans and mice. When immunized with external antigens, rabbits can produce a stronger immune response than humans and mice. Humans and mice produce their primary antibody repertoire by combining multiple VH, D, and JH gene fragments from the heavy chain and multiple V(γ) and J(γ) gene fragments from the light chain. In the second stage, somatic hypermutation causing gene rearrangements resulting in VJ and VDJ further enriches the antibody repertoire and increases the diversity of antibody affinities. Although the mechanism of production of the primary antibody repertoire in rabbits is similar to that in humans and mice, the mechanism of production of the antibody repertoire in the second stage includes not only a somatic hypermutation process, but also an additional gene conversion mechanism that further enriches the rabbit antibody repertoire. As a result, rabbit antibodies can recognize antigens that some mouse antibodies cannot. If you need to use antigens with weak immunogenicity in your experimental applications, it is a very wise strategy to choose the rabbit antibody system.

Simpler immunoglobulin structure

It is well known that immunoglobulins are divided into five classes defined by their heavy chain types: Cγ for IgG; Cμ for IgM; Cα for IgA; Cε for IgE and Cδ for IgD. Rabbit immunoglobulins were found to be divided into four classes (excluding IgD). The most abundant immunoglobulin in rabbit serum is IgG, with serum concentrations of 5-20 mg/ml. Unlike IgG from other animals, rabbit IgG has no subclasses. Compared to mouse and human IgG, rabbit IgG tends to have fewer amino acids in the N-terminal and D-E loops and has additional disulfide bonds in the variable region of the heavy chain, which may be responsible for making the rabbit monoclonal antibody more stable. It is this simpler structure and more stable nature of rabbit IgG that facilitates molecular cloning of key antibodies in antibody drug development and makes the results of various application experiments in the laboratory more stable.

Higher specificity and affinity

High affinity is a prerequisite for a successful immunoassay and a basic indicator of a good quality monoclonal antibody. Non-specific interactions of antibody drugs can cause side effects, so high affinity is important for the preparation of some good quality antibody drugs. Most monoclonal antibodies have dissociation constants (Kd) in the nanomolar or subnanomolar range, but rabbit monoclonal antibodies have higher affinities in the picomolar range. The high affinity and high specificity of rabbit monoclonal antibodies make them potential for better experimental applications. The excellent performance of rabbit monoclonal antibodies in IHC applications also supports our view. The simple and reliable rabbit monoclonal antibodies have become very popular among scientists.

Easy humanization

To reduce the immunogenicity of monoclonal antibody drugs, several methods have been developed to minimize the amount of animal genes in the antibody. The most widely used is CDR transplantation. The essence of this method is that the appropriate CDR coding region is inserted into the human antibody framework, and some structurally critical residues within the framework region are mutated back to the parental residues in order to restore the affinity and specificity of the original antigen. Although 90% of the sequence after CDR transplantation is of human origin, there are still some problems to be solved: first, it is still difficult to predict the specific effect of these specific residues on antibody specificity. Therefore, more in vitro and in vivo testing of the different humanized versions is needed. Second, CDR-transformed antibodies show reduced affinity for their antigens, and in vitro-based affinity maturation is needed to restore affinity in humanized antibodies.

Recently, a new humanization technique called Mutational Linage-Guided (MLG) humanization has been developed to facilitate RabMAb humanization. MLG humanization is conceptually and technically different from the CDR grafting method. The amino acid sequences of the heavy and light chain variable regions (VH and VL) from a collection of IgG sequences are aligned to form a phylogenetic tree. Related antibodies are grouped according to sequence similarity. Conserved sequences in the spectrally related group represent residues that are critical for IgG structure and function. Since these variable positions are usually derived from a set of antibodies from a parental B cell, they must have been efficiently scanned by the animal's immune system. Therefore, amino acid substitutions at these positions in humanized antibodies should be well tolerated and not sacrifice antibody specificity and affinity. More importantly, these changes were found not only in the framework region but also in the CDR. Therefore, MLG humanization can be applied to humanize both the framework region and the CDR. Due to the large number of rabbit spleen lymphocytes, sufficient biologically active RabMAb can be generated by MLG humanization to screen for well-performing humanized RabMAb.

High quality monoclonal antibody drug candidates

At the beginning of the 21st century, biopharmaceuticals are developing rapidly. Monoclonal antibodies have taken a large share of biologics. We also expect to find potential drugs to cure tumors and cancers by screening for high-quality monoclonal antibodies and drug targets. Rabbits also have an advantage over mice in this regard because the rabbit spleen contains 50 times more lymphocytes than the mouse spleen. Hundreds of antibody libraries can be generated from each immunized spleen, providing a greater number of independent monoclonal antibodies that recognize different epitopes. Thus, a set of biologically active RabMAb can be easily obtained for further selection of antibody drug primers. The robustness of RabMAb production provides a higher success rate, so RabMAb has the potential to obtain the most desirable drug in a relatively short time.

Rabbits are known to produce multiple antibodies against many antigens, including phosphopeptides, carbohydrates, and immunogens that are not immunogenic in mice. Rabbit polyclonal antibodies have proven to be very useful in the laboratory. However, inconsistencies during immunization and limited antibody production hampered their clinical use until rabbit monoclonal antibodies could be produced. However, the development of first-generation rabbit monoclonal antibodies was severely limited by the limitations of myeloma cell lines and was expensive due to patents. The emergence of second-generation rabbit monoclonal antibodies, however, cleverly circumvented the limitations of myeloma cells and successfully achieved further development of rabbit monoclonal antibodies by directly screening effective antibodies through fusion and phage display technology, genetically engineered antibody technology, and various expression and purification technologies.

Numerous RabMAb have been widely used for various applications in life science research IHC, WB, IP and FCM. RabMAb has proven to be an excellent reagent in immunohistochemistry (IHC) and performs extremely well in detecting post-translational modifications of proteins, such as phosphorylation and activation. In addition, a number of RabMAbs have been developed for the detection of biomarkers in targeted cancer therapies. The demand for rabbit monoclonal antibodies in scientific research is increasing day by day, so it is especially important to provide high-quality rabbit monoclonal antibody products.

We have now launched around 2000 rabbit monoclonal antibodies with high quality.

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