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Antibodies are large glycoproteins produced by the immune system to help defend the host against foreign invaders. They are Y-shaped molecules that are composed of two identical heavy and light polypeptide chains. One heavy and light chain associate via their N-terminals, forming a domain that will bind to its antigen. An antigen is a substance that initiates an immune response. It is typically a protein, but may also be a carbohydrate, small molecule or nucleotide. Each antibody will only recognize and bind to one specific epitope (i.e. site) on an antigen. This specific binding allows antibodies to be powerful research tools for the detection of a specific protein in an assay.

What is the difference between monoclonal and polyclonal antibodies?

Monoclonal antibodies are a homogenous population of antibodies that are produced by a single clone of plasma B cells. These antibodies bind to the same epitope on an antigen. Polyclonal antibodies are a heterogeneous mixture of antibodies that is produced by different clones of plasma B cells. The antibodies recognize the same antigen but bind to different epitopes on the antigen.

What are recombinant monoclonal antibodies?

Recombinant antibodies are monoclonal antibodies that are produced by molecular cloning techniques instead of traditional hybridoma-based technologies. In other words, hybridomas and animals are not needed to produce recombinant antibodies. Instead, genes for specific light and heavy antibody chains are inserted into expression vectors, which are subsequently introduced into expression host cells. The host cells produce the antibodies, which can then be collected. Advantages of recombinant monoclonal antibodies includes improved lot-to-lot consistency and reproducibility, ability to scale up to gram quantities, and opportunity for high-throughput, animal-free production.

How do you test for antibody specificity?

Bio-Techne has adopted the recommendations outlined by the International Working Group for Antibody Validation, which was published in 2016 in Nature Methods (Uhlen, M. et al. (2016) Nat. Methods 13:823), for antibody validation. The methods we utilize include genetic validation via gene editing and knockout cell lines, orthogonal validation using RNAscope^®in situ hybridization technology, independent antibody validation using several antibodies for the same protein, validation using a tagged protein standard, and validation across multiple cell lines, including positive and negative expressing cells, and multiple species. Visit our Antibodies Built for Reproducibility page on the R&D Systems site to learn more.

How do you test for antibody reproducibility?

Bio-Techne takes rigorous steps toward producing antibodies that display the same high specificity from lot-to-lot. We develop and manufacture over 90% of our products in house, giving us control over product development and testing. The immunogens we use to produce our antibodies are designed to ensure correct epitope presentation using our high-quality proteins, transfected cells, or carefully selected peptide sequences. The new antibody lots are then screened beside previous commercial lots to ensure the new lots exhibit the same sensitivity and specificity. Visit our Antibodies Built for Reproducibility page on the R&D Systems site to learn more.