A primary antibody is an immunoglobulin that specifically binds to a particular protein or other biomolecule of research interest for the purpose of purifying or detecting and measuring it. Primary antibodies are developed as polyclonal or monoclonal antibodies using mouse, rat, rabbit, goat, and other animal species as hosts. They are produced and supplied in various forms, ranging from crude antiserum to antigen-purified preparations. Primary antibodies for frequently researched targets are also available conjugated to fluorescent dyes or biotin.

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