Polyclonal antibodies (pAbs)

Polyclonal antibodies (pAbs) are a complex mixture of immunoglobulin molecules produced by multiple B cell clones, each recognizing a different epitope on the same antigen (NIH, 2023). This heterogeneity allows for a more comprehensive immune response compared to monoclonal antibodies, as they can neutralize pathogens through multiple binding sites and facilitate clearance via opsonization and complement activation (StatPearls, 2023). Historically, pAbs have been utilized as antiserum for the immediate treatment of toxin exposure, such as snake venom or tetanus, and as intravenous immunoglobulin (IVIG) for primary immunodeficiencies and autoimmune disorders (Wikipedia, 2024). In modern medicine, they are also employed as immunosuppressants, such as antithymocyte globulin used in organ transplantation to deplete T cells. Despite their efficacy, pAbs face significant therapeutic challenges, including the risk of serum sickness, potential for cross-reactivity, and inherent batch-to-batch variability due to their biological origin (PubMed, 2022). They are typically produced by injecting an antigen into a host animal, such as a rabbit, goat, or horse, and then extracting the antibodies from the serum. Because they target multiple epitopes, they are less likely to be affected by minor changes in the antigen's structure, such as those caused by genetic polymorphism or mutation.

Other names

AntiserumPolyvalent antibodiesHeterogeneous antibodiespAb

Binding to multiple epitopes on a target antigen to facilitate neutralization, agglutination, and immune-mediated clearance.