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Primary and Secondary Antibodies

This product group includes primary antibodies to detect reporter molecules and protein tags used in Promega technologies, as well as labeled secondary antibodies and detection reagents for use in immunoassays.

Primary antibodies include anti-luciferase antibodies for detection of firefly and NanoLuc® luciferases, anti-HaloTag® antibody for detection of Halotag-labeled proteins, and anti-LgBiT antibody for use with HiBiT or NanoBiT® protein tagging systems.

Secondary antibodies include anti-human, anti-rabbit and anti-mouse antibody conjugates for use in blotting and ELISA immunoassays.

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Protein Detected

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What are Primary and Secondary Antibodies?

A primary antibody is used to bind directly to a protein antigen. The variable region on a primary antibody binds to a specific epitope on the target antigen. Primary antibodies are used to detect and bind to target antigens in immunoassay applications such as Western blots and ELISAs. 

Secondary antibodies are labeled antibodies that allow bound primary antibodies to be detected and quantified. Secondary antibodies bind to primary antibodies, but not to antigens present in the sample being interrogated. Secondary antibodies are therefore raised in a species that differ from the primary antibody and do not share cross-reactivity. Secondary antibodies can be labeled with fluorophores, enzymes or radiolabels, allowing the amount of bound primary antibody to be quantified using a fluorescent, chemiluminescent, colorimetric or radioactive signal. 

Secondary antibodies are typically polyclonal antisera raised against immunoglobulins and labeled with standard commonly used enzymes such as horseradish peroxidase or alkaline phosphatase.