Custom polyclonal antibodies

The choice of the antigen is a critical step to obtain successful polyclonal antibodies. ProteoGenix offers the possibility to use (and synthetize for you) 3 types of antigens: proteins, peptides and DNA. Each of these antigens have their own advantages and drawbacks and are especially recommended in specific cases:

• Proteins: when the protein (native or recombinant) is available this is generally the best option. This method is cost efficient and results in a pool of polyclonal antibodies directed against a plethora of epitopes throughout the sequence. This type of antibodies is very likely to recognize the native protein and thus it is specially recommended when the final application requires native conditions (IHC, IP, FC…). On the other hand, these antibodies are more likely to recognize other proteins with homologous epitopes, which may lead to non-specific cross reaction. They are therefore less adapted if specificity is an issue in the assay. Finally, some recombinant proteins are difficult and/or expensive to produce or might not match all the characteristics of the native protein, in these cases other alternatives are best suited.
• Peptides: when the protein is not available or a high degree of specificity is required, short peptides are very cost-efficient alternative. Thanks to our expertise, we will predict and synthetize the best epitopes of the protein to use them as antigens. This will result in a pool of polyclonal antibodies recognizing a restricted number of epitopes (equal to the number of peptides used), thus these antibodies are more specific. Because we can only use linear epitopes for this type of projects, these antibodies are more likely to succeed in applications where the protein is denatured (e.g. WB). They are also particularly useful when we want to develop highly specific antibodies (against PTM, members of a conserved family, mutants…).
• DNA: is the most recent and challenging approach to develop polyclonal antibodies. It combines the advantages of the two previous methods: it allows to elicit and rise antibodies against all the epitopes present in the native protein even when the protein is difficult to produce. This approach is recommended when other applications have not succeeded in the past for hard-to-produce antigens.

Of course, your dedicated pHd expert will help you design the best antigen for your specific project.

We offer 9 species : rabbit, chicken, mouse, rat, guinea pig, goat, sheep, llama, alpaca

The most popular host to develop polyclonal antibodies is rabbits. Their good immune response and size allow to obtain ~2mg of specific antibodies per animal. When this species is not adapted for the downstream application, rats and guinea pigs are very good alternatives as well. At ProteoGenix we also offer mice immunization programs, but due to the small size of these animals we obtain 10-100 times less antibodies from them.

If the protein antigen is highly conserved in mammals, the most adapted species is chicken. These animals produce IgY instead of IgG that they accumulate in the egg yolk. This allows for the purification of the final antibodies directly from eggs and therefore we obtain larger amounts of antibodies (~10 mg per animal).

Finally, if very large amounts of antibodies are expected, we can also immunize goats and sheep to obtain ~40 mg per animal.

The standard immunization protocol is 51 days. However, if you are in a hurry we offer an optional service with a 28 days turnaround. This Expressway protocol is only available for rabbits.

In most cases, we will guarantee that the antibodies work in ELISA as well as a minimum quantity of final product.

Yes, of course. Just let us know which samples you would like to receive and we will plan it for you. Our regular protocols include an ELISA titration after the 3rd immunization.

ProteoGenix is the expert of complex projects. We have experience with difficult targets and are confident in our ability to deliver.

In the rare case where the titer does not reach our guarantee we will discuss with you the reasons why this may have happened. Depending on the analysis, we can propose you three alternatives:

• Do some extra boosts free of charge
• Restart the project free of charge
• Cancel the project and refund you all the invoice except for the set-up fee

Not in all cases. Purification steps concentrate the final product, increasing the signal strength and lowering the total volume that must be used in the final application. Moreover, they help reduce non-specific reactivity, making the final product more specific and decreasing the signal-to-noise ratio. If these are not an issue in your final application, purification might not be necessary in your case!