Ever wonder about using chicken polyclonals? Or maybe this is the first time you have heard of them? Here is our list of pros and cons when it comes to the nature and use of chicken IgY as research tools.
We are in the business of providing high-quality chicken IgY because we think it is well worth your consideration. For examples of publications using our chicken IgY antibodies, please take a look at our News section and our Customer Success Blog (highlighting custom antibodies).
9 Major Advantages to Using Chicken Polyclonal Antibodies
1. Higher titers against highly-conserved mammalian gene products
Since chickens are at least 100 million years removed from mammals, they tend to recognize any mammalian gene product as foreign and mount vigorous immune responses. Consequently, chickens can be particularly advantageous as a host when raising antibodies against highly conserved mammalian proteins, where there are only a few differences in the amino acid sequence of the target protein and the hosts homolog, making them only weakly immunogenic in mammalian hosts.
2. Easier double (or multiplex) immunostaining
Chicken IgY antibodies are particularly useful in multiplex staining experiments. Chicken IgY antibodies can be used together with mouse and rabbit antibodies without the danger of cross-reactivity. Also, secondary antibodies against chicken IgYs do not cross-react with mammalian IgG. (See Chicken Polyclonals in Multiplex Immunofluorescence).
3. Cost-effective and longer-lasting
The price of chicken antibodies is considerably cheaper if you compare equivalent degrees of purification. The price, for example, of about 1.5 grams of protein A-purified rabbit IgY is about twice that of 1.5 grams of purified chicken IgY. The shelf life of our >90% IgY antibody preparations is potentially 5 years or more at 4˚C. In contrast, rabbit serum (which is what most companies provide) has only a limited shelf-life at 4˚C (measured in weeks-to-months), and some biological activity is lost when frozen. The cost of having rabbit antibodies purified to comparable purities (i.e., protein A-purified) is very high.
4. Higher signals
Chicken IgY antibodies have a higher glycosylation index than IgG antibodies, allowing greater labeling with HRP and other antibody tags when using reagents targeting the sugars on the antibody. This produces higher signals.
5. Animal-friendly
We purify the antibodies from eggs, not serum. With rabbits, in contrast, serum is obtained by restraining the animals, and performing ear bleeds or cardiac puncture. It is simply a more humane way to produce antibodies.
6. Nearly unlimited quantities
We collect about 18 "immune eggs" from each hen, but only use 6 "immune eggs" to produce your IgY preparation. We then store the remaining 12 "immune eggs" in the refrigerator, in case you need more antibody down the road. Moreover, we can continue to house the hens (for an additional charge), in case you want us to perform additional injections (see How long does it take to make a high quality chicken antibody?).
7. Non-mammalian-reactive Fc domain within the stem portion of a chicken IgY
The Fc domain of chicken IgY antibodies is different from that of mammalian IgG antibodies. This provides several advantages over rabbit (or other mammalian) IgGs: • It reduces the likelihood of having false positives in diagnostic applications, since it is the mammalian Fc domain that binds "rheumatoid factors" found in the serum of animals (or humans) with chronic inflammatory diseases.or • The chicken IgY Fc domain does not activate mammalian complement systems, allowing the use of chicken IgYs in in vivo applications. • The chicken IgY Fc domain does not bind to mammalian Fc receptors, avoiding non-specific binding to cells expressing such receptors (e.g., macrophages and dendritic cells).
8. No reactivity with human anti-animal antibodies in assay samples
Chicken IgY antibodies which will not be recognized by any human anti-animal (mammalian) antibodies present in assay samples. Human anti-animal (mammalian antibodies (such as human anti-mouse antibodies, HAMA) in blood/serum samples can cause interference in ELISA assays utilizing mammalian antibodies. (see Endogenous Heterophile and Human anti-animal Antibodies Mode of Action with Respect to ELISA Interference).
9. Higher carbohydrate content
In applications that require binding of antibody to solid surfaces (e.g., ELISA, antibody microarray, etc.), one can absorb about twice as much chicken IgY to a glass or plastic surface than rabbit IgG. This is presumably due to the higher carbohydrate content in chicken IgY (about 3% carbohydrate as compared to about 1% in rabbit IgG). The higher content of carbohydrate allows a higher degree of enzyme- or hapten-conjugation away from the antigen-binding regions of the antibody. For example, one can easily conjugate 15-20 biotins per chicken IgY using hydrazide carbohydrate chemistry, as compared to 7-10 per rabbit IgG.
Four Minor Disadvantages to Using Chicken Polyclonal Antibodies
There are a few potential downsides of chicken IgY, and some minor inconveniences. Read below to learn how Aves Labs' PrecipHen® Immunoprecipitation Reagent can help overcome a common disadvantage of using Protein A and Protein G reagents for immunoprecipitation. Our PrecipHen® is made from goat anti-chicken IgY antibodies covalently attached to agarose beads. It is designed for use with chicken antibodies in immunoprecipitation (IP), chromatin immunoprecipitation (ChIP), and protein purification applications.
- Labs that use birds as a primary experimental animal may find chicken IgY difficult to use, in much the same way that mouse labs have difficultly using mouse antibodies: secondary antibodies cross-react with endogenous antibodies in the experimental animals. For this reason, we recommend that chicken labs use other host animals for their antibody production.
- In applications that require Fab fragments, chicken IgY may be less cost-effective than rabbit IgG. It is much more expensive to produce Fab fragments from chicken IgY molecules than from rabbit IgG’s because chicken IgY lacks the sequence to which protein A binds, necessitating the use of anti-chicken IgY-stem antibodies to separate the IgY-stems from the Fab fragments.
- Since chicken IgY does not have sequences that bind proteins A or Protein G, labs that tend to use Protein A or Protein G reagents for immunoprecipitation need to use an alternative reagent. We provide our PrecipHen® product, an affinity-purified goat anti-chicken IgY coupled to agarose, to help customers easily overcome this issue.
- Presumably due to their high carbohydrate content, PVDF and other nylon-based membranes bind chicken antibodies non-specifically. However, this can be overcome by using pure nitrocellulose membranes instead of PVDF. For most purposes, nitrocellulose membranes substitute beautifully for other nylon-based membranes.