Polyclonal antibodies are antibodies that are derived from different cell lines.

These antibodies are typically produced by immunization of a suitable mammal, such as a mouse or rabbit. An antigen is injected into the mammal. This induces the B-lymphocytes to produce IgG immunoglobulins specific for the antigen. This IgG is purified from the mammal’s serum.

Several lines of B-lymphocytes produce these antibodies. These antibodies have specificity for different epitopes.

By contrast, monoclonal antibodies are derived from a single cell line.