Popular Custom Antibody Services

A quality antibody is one that bears the appropriate sensitivity and specificity best suited for your target experimental assay. Not all antibodies work across a wide range of applications because each application has different performance specifications. For example, antibodies used in Western blots recognize denatured, linearized protein antigens, while flow cytometry, sandwich ELISA, IF, and functional assays all require antibodies that recognize the natural, folded shape of the protein.

As you begin your quest to generate a custom antibody that is best suited for your research needs, do ask yourself these basic questions:

• What research application(s) am I planning to this custom antibody in?
• Is a polyclonal or monoclonal antibody better suited for my assay?
• Where is my protein/epitope of interest located?
• Is the epitope unique or common, linear or conformational, buried or surface exposed? Is it subject to post translational modifications?

Being clear on the answers to such questions will ensure that you begin your antibody generation process under optimal conditions, and ultimately maximize your success at generating your desired antibody.

Both polyclonal and monoclonal antibodies have their own advantages and disadvantages, making them useful for different research applications.

Polyclonal Antibodies

Polyclonal antibodies (pAbs) are comprised of a mixed population of antibodies and are therefore capable of recognizing multiple epitopes on any one antigen.

Advantages:

• Can help to increase the signal produced by the target protein as the antibody will bind to more than one epitope.
• More tolerant of minor changes in the antigen, e.g. polymorphism, heterogeneity of glycosylation, or slight denaturation.
• Useful when the nature of the antigen is unknown.
• More robust detection due to multiple epitopes.
• Generally more stable, quick and inexpensive to produce compared to mAbs.

Disadvantages:

• Prone to batch-to-batch variability.
• Susceptible to cross-reactivity with immunogen due to recognition of multiple epitopes.

Monoclonal Antibodies

Compared to pAbs, mAbs are more specific because they stem from a single antibody clone and thus recognize a single epitope on an antigen.

Advantages:

• Hybridoma cell lines provide a way to produce unlimited quantities of homogenous, highly specific mAbs.
• If conditions are kept constant, experiments using mAbs can be highly reproducible.
• All mAb batches will be identical and specific to just one epitope, which is a critical advantage when manufacturing procedures must be standardized e.g. clinical tests and therapeutic treatments.
• High specificity, as well as low background noise and cross-reactivity ensures high mAb efficiency and reproducibility in experimental procedures (western blot/IP, affinity purification, ELISA, mass spectrometry etc.).
• Specific antibody characteristics can be identified and selected for. For example, sensitivity requirements and cross-reactivity levels can be specified and monoclonal antibodies screened to identify any cell lines exhibiting the required characteristics.

Disadvantages:

• mAbs may be too specific (e.g. less likely to detect across a range of species).
• More vulnerable to the loss of epitope through chemical treatment of the antigen than polyclonal antibodies. This can be offset by pooling two or more monoclonal antibodies to the same antigen.
• Compared to pAbs, mAbs are more expensive and take longer to produce.

The antigens can be grouped into seven general categories:

• Synthetic peptides (<20 aa)
• Recombinant protein fragments or full length proteins
• Native proteins purified directly from its natural source
• Whole cells
• DNA vaccine
• Small molecule
• Antibody (Anti-idiotype antibody)

Each of these categories has different strengths and weaknesses and it is important to review which type of antigen is most suited for your antibody generation project.