From analytical applications (e.g., Western blot, ELISA, and Immunostaining) to diagnostics (e.g., detection of tumor-associated antigens: PDL-1, estrogen receptor, and HER2) and even as therapeutics (e.g., Brolucizumab, Eptinezumab), rabbit monoclonal antibodies are attractive and powerful tools.
Pei Liu, Ph.D.Senior Scientist,Antibody Department, GenScript
“Compared to mouse, rabbit monoclonal antibodies have higher affinity and specificity for their targets”.
For therapeutic use, the higher sensitivity and epitope specificity of rabbit monoclonal antibodies translate to reduced off-target binding and lower dosage requirements, ultimately minimizing the potential for toxicity.
Broader Antigen Detection Capabilities- Rabbit monoclonal antibodies offer more expansive target recognition capabilities ideal for diagnostics and therapeutics. Broader paratope diversity is underscored by the unique processes giving rise to the primary antibody repertoire in rabbits, which depends on somatic hypermutations, as occurs in mice, but also on somatic gene conversion, a type of homologous recombination predominant in the chicken and rabbit.
Expanded Opportunities for Screening - The rabbit’s general larger size, notably larger spleen and greater blood volume and bone marrow tissue, translates to greater opportunities for isolating B cells and finding more monoclonal antibodies with desirable epitope specificities.
Cross-reactivity is a Plus- An added advantage of rabbit-derived monoclonal antibodies is their cross-reactivity with epitopes in mouse and human antigens, which is helpful in preclinical evaluation and characterization of human disease mouse models.
Sasidhar Murikinati, Ph.D.
Regional Marketing Manager, ProBio, GenScript
“The rabbit’s evolutionary distance from human is further than that of rodents, allowing the rabbit immune system to generate monoclonal antibodies against human antigens commonly non-immunogenic in mice.”
Low Immunogenicity Antigens-Not a Problem- The rabbit’s immune system can recognize human antigen epitopes that are otherwise ignored by that of rodents.
If your target of interest happens to have low immunogenicity, as is typical for small molecules, rabbits may be your best choice for monoclonal antibody development. Unlike rodents, rabbits can mount a stronger immune response against small molecules, haptens, and post-translational modifications (e.g., AMPylated peptides and phosphorylated peptides).
Dorothea Hopfner, Ph.D. Candidate,
Department of Chemistry, Technical University Munich
“Commercially available polyclonal antibodies to detect AMPylated proteins were not specific enough to detect AMPylated proteins in complex samples for target identification.”
“Anti-AMP monoclonal antibodies were developed because of their potential as an orthogonal method that may be broadly used by any lab.”
About critical considerations to keep in mind when developing monoclonal antibodies against post-translational modifications, Dorothea Hopfner shared that antibodies must-
In developing anti-PTM antibodies, synthetic peptides are an asset. “Synthetic peptides can significantly help in anti-PTM antibody development, and the bottleneck of antibody candidate selection can be overcome by including native modified protein for screening when immunizing with peptides,” said Dorothea Hopfner.
Jo Morris, Ph.D.
Professor of Molecular Genetics, Institute of Cancer and Genomic Sciences, University of Birmingham
“GenScript generated an antibody using a peptide of phosphorylated BRCA1 and this was a very useful tool.” The anti-BRCA1 (pS114) rabbit polyclonal antibody reagent was specific, evidenced by the lack of signal with unphosphorylated BRCA1.
Overall, the enhanced properties of rabbit antibodies represent an advantage for applications requiring high sensitivity and epitope specificity. Whether you select a rabbit polyclonal or monoclonal antibody ultimately depends on your specific needs. For the detection of AMPylated proteins, Dorothea Hopfner required a long-lasting, consistent, and reliable antibody source to support characterization and validation efforts. Therefore, a rabbit monoclonal antibody was the best choice to prevent batch-to-batch reproducibility issues.