Rabbit Polyclonal Antibodies

Polyclonal antibodies are a heterogeneous mixture of antibodies that all recognize the same protein. They offer many advantages for scientific research, including the capacity to improve assay sensitivity when performing techniques such as western blotting (WB), immunocytochemistry (ICC), and enzyme-linked immunosorbent assay (ELISA), which is the result of multiple antibodies binding to different epitopes on the same target of interest. This can be especially useful when detecting scarce targets, or proteins that are likely to change conformation. Another important benefit of using polyclonal antibodies is that, compared to monoclonal antibodies, they are more likely to detect proteins in which certain epitopes have been masked by fixation, crosslinking, or the formation of protein complexes. Epitope masking can be especially problematic for techniques such as immunohistochemistry (IHC), immunoprecipitation (IP), or chromatin immunoprecipitation (ChIP). Polyclonal antibodies also tend to have broader application functionality than monoclonal antibodies, meaning they can provide a degree of experimental consistency by allowing for the same antibody to be used across several different immunoassay formats. In addition, polyclonal antibodies are typically available sooner than monoclonal antibodies when a new protein target is discovered due to their shorter production time. Polyclonal antibodies are most commonly produced in rabbits. One reason for this is that rabbits are fairly easy to work with, being both quick to breed and mature into adults, and relatively inexpensive to feed and care for – compared to the production of chicken polyclonal antibodies and goat polyclonal antibodies. Rabbits also have a more diverse immune repertoire than mice (the traditional host species used for monoclonal antibody production) and can thus provide more extensive target recognition. As such, rabbit polyclonal antibodies are widely used for detecting post-translational modifications such as phosphorylation, methylation, and acetylation, as well as for detecting targets that are known to present challenges for murine antibody production. These include small peptide antigens, which have only a limited number of epitopes available for antibody binding, and human proteins that share a high degree of sequence homology with the murine equivalents. Because the evolutionary distance between humans and rabbits is greater than that between humans and mice, some proteins are inherently more immunogenic in rabbits. The larger size of rabbits in comparison to mice also means that they produce higher antibody yields, which can be useful when identifying the best performing host animals during early antibody development.