Why are antibodies so rarely raised in chickens?
March 30, 2011 7:36 AM   Subscribe

Why isn't it more common to raise antibodies in chickens and then harvest the antibodies from egg yolk? It seems like the turnaround time is way better than with rabbit or goat serum antibodies, and plus chickens are pretty easy to take care of. I imagine purifying yolk would be easier than serum, too. Is there a downside I'm not seeing, perhaps something you lose by going with an avian rather than a mammalian host?
posted by nicolas léonard sadi carnot to Science & Nature (8 answers total)
Well, I can think of one major downside: people with egg or chicken allergies or food sensitivities cannot take a vaccine made via eggs. My mother and I both have this problem.

Of course, this is a problem with nearly every animal production route like this. A friend of mine nearly died from being given anti-venom for a snake bite made via horses - he's apparently very allergic to horses, but never knew until he was given the anti-venom.
posted by strixus at 7:39 AM on March 30, 2011

Wikipedia has a decent sub-article on animal selection in polyclonal antibody production. It discusses some of the pros and cons of using chickens.
posted by jedicus at 7:45 AM on March 30, 2011

Been there, done that. With sound effects.
posted by greatgefilte at 8:27 AM on March 30, 2011

Also, what jedicus said. The chicken antibodies are definitely sufficient for many investigative purposes, but not for others. That said, from what I can recall, most people I ran into just weren't aware of the possibility of using chickens instead of mice/rabbits/etc.
posted by greatgefilte at 8:34 AM on March 30, 2011

Most small animal units are set up to grow mammals like rabbits, whereas chickens need a whole different facility and different husbandry skills too. Also rabbits can be kept in a relatively small area, mice or rats even more so. Keeping chickens in close quarters is more troublesome ethically and more difficult to keep them stress-free and healthy. So rabbits end up being a lot easier for many Universities or research organisations to keep. Larger animals like goats are also more difficult of course, but for research purposes rabbits are generally big enough.

I don't see any reason why purifying from yolk is any easier than purifying from serum, unless there's some specific biological property of yolk I'm missing? They're both complex physiological fluids. Presumably the people that make anti-bodies have a method optimised for whatever they use, which, in turn, probably makes them more resistant to change.
posted by shelleycat at 1:56 PM on March 30, 2011

In my field of research chicken antibodies are rarely used, but there's no reason why more couldn't be. From what I've been told, they're usually have a fabulous binding characteristics. They would also provide flexibility for multi-colour immunohistochemistry stains, when the more antibodies you have from different species, the better.

For antibody therapy in humans (and in research, for that matter), the aim nowadays is to make monoclonal antibodies, which can be manufactured from a cell line.

In research, I suspect animal choice is largely historical: The rabbit was the most commonly used animal 20 years ago, and remains so today. Well, at least for polyclonal antibodies. Monoclonals are almost always from mice or rats, and I'm not sure why that is. It may be that the technique for making B cell hybridomas (immortalised B cell lines from which monoclonal Abs are harvested) is easiest for rodent B cells, or perhaps this too is historical.

Also, the purification may not be easier for chickens, despite a better initial yield. If Protein A and/or protein G were not as as good for chicken antibodies as they are for mammalian Ig, for example, then making highly purified Chicken Ig might be trickier.

Finally, I wonder whether, if a biotech company were to have all of the facilities for growing chicken eggs and purifying biological material from them, there might simply be more money to be made in growing vaccines instead.
posted by kisch mokusch at 2:45 PM on March 30, 2011

Best answer: Just noticed that a lot of you were checking out our website. We are a polyclonal antibody producer and we only use hens. Hope you don't mind if I reply to some of your queries:

If you need a lot of antibodies, using chickens is a great idea -- one hen can produce as much antibody (purified from eggs) as a goat. From one egg, you can purify 100 mg IgY (the IgG equivalent in hens). This means that over the course of a month, you can purify 2 grams of IgY, which is about 10 times the amount you'd get from a rabbit...

It is a bit difficult to purify IgY from the yolk of an egg, but there are many commercial kits available -- and the final IgY prep is similar to a protein A affinity-puriified serum IgG fraction from a mammal, because there is only one immunoglobulin class (IgY) in the egg yolk.

And, of course, it's more humane to collect eggs than to bleed animals. It's also easy to have a store of antibodies in the fridge (in eggs) and by sampling various eggs, you can go back and purify the eggs that have the highest titer.

But, often, the most important reason that researchers choose hens to immunize is because hens are not mammals and as such, may produce a higher titer antibody to conserved mammalian proteins.

Thanks for listening!
posted by kcoulter at 5:14 AM on March 31, 2011 [3 favorites]

I did this with an CHO lysate. I also did rabbits. My expectation was that since hampsters and chickens diverged much longer ago that hampsters and rabbits, there would be fewer homologous proteins in between the chickens and the CHO cells and I would get wider coverage with the IgY's.

IgY yields were good, but coverage was not as good as with the rabbit serum. That may be due to this:

"Rabbits have a unique immune system. During T cell-dependent immune responses in mouse and human, Ig genes diversify by somatic hypermutation within germinal centers. Rabbits, in addition to using somatic hypermutation to diversify their IgH genes, use a somatic gene conversion-like mechanism, which involves homologous recombination between upstream VH gene segments and the rearranged VDJ genes."
posted by Kid Charlemagne at 9:04 AM on April 1, 2011

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