Polyclonal antibodies (PAbs) are a mixture of antibodies that are secreted by different B cell lineages. These antibodies are actually a collection of immunoglobulin molecules that react against a specific antigen, each identifying a different epitope on an antigen.
pAbs can be made in large quantities depending on the size of the animal used. While production normally comes from rabbit hosts, polyclonal antibodies can also be created in larger animals such as sheep and goats. This provides researchers with antibody quantities suitable to support a large-scale screen.
Because polyclonal antibodies contain a heterogeneous mixture of IgGs against the whole antigen, they are able to bind to many different epitopes of a single antigen. Therefore any small change in the epitopes of an antigen is less likely to affect pAbs making them more stable.
Polyclonal antibodies also have a high sensitivity to the target protein due to their ability to recognize many different epitopes of the target protein.