Polyclonal antibodies are a type of antibody produced by different immune cells in response to a specific antigen. They are generated from multiple B-cell lineages, which means they can recognize and bind to various parts of the same antigen. This diversity allows them to be effective in neutralizing pathogens and marking them for destruction by other immune cells. These antibodies are commonly used in research, diagnostics, and therapeutic applications. For example, they can be employed in ELISA tests to detect specific proteins or in immunotherapy to treat certain diseases. Their broad reactivity makes them valuable tools in both clinical and laboratory settings.