Genetic experts - any info on B21 gene?

[Henk69]

Quote:
hello Henk.

inoculating=vaccination (vaccinating). Has vaccinating in Europe led to more virulent strains of Marek's? How are they more virulent? Does the vaccine not work on new strains? Marek's is worldwide and long lived on a premises (50+ years) so would it matter if all or none were vaccinated? Any advantage or promise of birds that get classic Marek's but then fully recover?

Recover? Unlikely. Less animals get sick or the onset is postponed (past breeding age).
But vaccinated lines of chickens need to be vaccinated as chicks.
If one sells such chickens and the new owner doesn't do that there is a disaster if the virus is present in the sold chickens.
Which is likely.

 

[tadkerson]

Quote:
What you are asking about is very complicated. I am going to try and simplify the answer.

Birds have a group of genes found on a chromosome that are called the " major histocompatibility complex". These genes have to work together to produce antibodies that can attack the different viruses and bacteria that invade the body. The body has to first recognize the virus as being foreign then make the antibodies that attack the virus. The instructions for making the antibodies are found in the histocompatibility complex. This takes time and if a bird can put together the correct combination of proteins ( antibodies) - the bird will kill the viruses or suppress the virus population and not die from the disease. The B21 is one of a series of genes found in the histocompatibility complex. It contains part of the instructions for making the antibodies.

Viruses have a protein shell that surrounds the DNA or RNA found on the inside of the virus. It is the proteins in the shell that are recognized as foreign by the T cells ( special white blood cells) . The information is passed along to the B cells ( special white blood cells)- the B cells then make the antibodies that help destroy the virus. The antibodies are specific to the protein coat found on the virus. Like a lock and key. The lock is the protein on the virus and the key is the antibody. If the protein coat on a virus changes the B cells have to come up with a protein recipe ( from the histocompatibility complex) that will fit the proteins on the virus. If it can not come up with a recipe the bird dies from the Mareks disease.

An inoculation or vaccination inject the protein coat into the chick- the chick can then build up antibodies to the virus without actually developing the disease. When the virus actually does infect the bird- the B cells know the recipe for making the antibodies and the virus is suppressed or destroyed.

The evolutionary trend is the changes in the protein coat. Viruses pick up different proteins from different chickens. The more chickens the virus goes through the greater the chances of the virus protein coat changing. One chicken passes the virus to another chicken etc. etc.

Vaccinated chickens can pass the virus onto other vaccinated chickens or to non-vaccinated chickens. This is how the virus changes and picks up new proteins it adds to its coat.

Resistance is developed in the histocompatibility complex- birds that are resistant contain the genes that make the antibodies- they can pass the information on to their offspring. A chicken can not pass on the B cell memory concerning how to make the antibodies.

Tim

 

[Year of the Rooster]

Quote:
What you are asking about is very complicated. I am going to try and simplify the answer.

Birds have a group of genes found on a chromosome that are called the " major histocompatibility complex". These genes have to work together to produce antibodies that can attack the different viruses and bacteria that invade the body. The body has to first recognize the virus as being foreign then make the antibodies that attack the virus. The instructions for making the antibodies are found in the histocompatibility complex. This takes time and if a bird can put together the correct combination of proteins ( antibodies) - the bird will kill the viruses or suppress the virus population and not die from the disease. The B21 is one of a series of genes found in the histocompatibility complex. It contains part of the instructions for making the antibodies.

Viruses have a protein shell that surrounds the DNA or RNA found on the inside of the virus. It is the proteins in the shell that are recognized as foreign by the T cells ( special white blood cells) . The information is passed along to the B cells ( special white blood cells)- the B cells then make the antibodies that help destroy the virus. The antibodies are specific to the protein coat found on the virus. Like a lock and key. The lock is the protein on the virus and the key is the antibody. If the protein coat on a virus changes the B cells have to come up with a protein recipe ( from the histocompatibility complex) that will fit the proteins on the virus. If it can not come up with a recipe the bird dies from the Mareks disease.

An inoculation or vaccination inject the protein coat into the chick- the chick can then build up antibodies to the virus without actually developing the disease. When the virus actually does infect the bird- the B cells know the recipe for making the antibodies and the virus is suppressed or destroyed.

The evolutionary trend is the changes in the protein coat. Viruses pick up different proteins from different chickens. The more chickens the virus goes through the greater the chances of the virus protein coat changing. One chicken passes the virus to another chicken etc. etc.

Vaccinated chickens can pass the virus onto other vaccinated chickens or to non-vaccinated chickens. This is how the virus changes and picks up new proteins it adds to its coat.

Resistance is developed in the histocompatibility complex- birds that are resistant contain the genes that make the antibodies- they can pass the information on to their offspring. A chicken can not pass on the B cell memory concerning how to make the antibodies.

Tim

Awesome explanation, Tim!

Thank you!

 

[ChicKat]

X2 Thank you very much Tim for taking the time to provide a simplified and very easy to understand explaination.

 

[ChicKat]

Here is a link to the abstract of an article regarding B21 genetic resistance:

http://www.ncbi.nlm.nih.gov/pubmed/20138080

and another article about white leghorn resistance to MD

http://ps.fass.org/content/80/8/1064.full.pdf

Here is another article about resistance...this one regarding the absorbtion of Vitamin D

http://ps.fass.org/content/87/6/1112.full

 

[weechickenhawk]

What you are asking about is very complicated. I am going to try and simplify the answer.


Birds have a group of genes found on a chromosome that are  called the " major histocompatibility complex". These genes have to work together to produce antibodies that can attack the different viruses and bacteria that invade the body. The body has to first recognize the virus as being foreign then make the antibodies that attack the virus. The instructions for making the antibodies are found in the histocompatibility complex. This takes time and if a bird can put together the correct combination of proteins ( antibodies) - the bird will kill the viruses or suppress the virus population and not die from the disease. The B21 is one of a series of genes found in the histocompatibility complex. It contains part of the instructions for making the antibodies.


Viruses have a protein shell that surrounds the DNA or RNA found on the inside of the virus. It is the proteins in the shell that are recognized as foreign by the T cells ( special white blood cells) . The information is passed along to the B cells ( special white blood cells)- the B cells then make the antibodies that help destroy the virus. The antibodies are specific to the protein coat found on the virus. Like a lock and key. The lock is the protein on the virus and the key is the antibody. If the protein coat on a virus changes the B cells have to come up with a protein recipe ( from the histocompatibility complex) that will fit the proteins on the virus. If it can not come up with a recipe the bird dies from the Mareks disease.


An inoculation or vaccination inject the protein coat into the chick- the chick can then build up antibodies to the virus without actually developing the disease. When the virus actually does infect the bird- the B cells know the recipe for making the antibodies and the virus is suppressed or destroyed.


The evolutionary trend is the changes in the protein coat. Viruses pick up different proteins from different chickens. The more chickens the virus goes through the greater the chances of the virus protein coat changing. One chicken passes the virus to another chicken etc. etc.


Vaccinated chickens can pass the virus onto other vaccinated chickens or to non-vaccinated chickens. This is how the virus changes and picks up new proteins it adds to its coat.


Resistance is developed in the  histocompatibility complex- birds that are resistant contain the genes that make the antibodies- they can pass the information on to their offspring.  A chicken can not pass on the B cell memory concerning  how to make the antibodies.


Tim

Wow Tim that was an awesome explanation. Even I could totally understand it.

 

[nonnagrace]

I had two araucana hens of about 8 months, one which started eating less and was very thin, it died at the vets at the new year and post mortem found abcesses in the head and gizzard. my other one took ill just afterwards and is just wasting away although still eating well, she has been wormed and had antibiotics but now the vet thinks she should be euthanized, does this sound like mareks although tests did not show this at the first ones post mortem and could they have had it when I got them 4 months ago, as I also got a speckledy at the same time from the same breeder, I am worried about it and the rest of my hens. will they all die too?, I would be grateful of any information

 

[arthurt]

Thanks Tim, that was of great help mate

 

[ChicKat]

I had two araucana hens of about 8 months, one which started eating less and was very thin, it died at the vets at the new year and post mortem found abcesses in the head and gizzard. my other one took ill just afterwards and is just wasting away although still eating well, she has been wormed and had antibiotics but now the vet thinks she should be euthanized, does this sound like mareks although tests did not show this at the first ones post mortem and could they have had it when I got them 4 months ago, as I also got a speckledy at the same time from the same breeder, I am worried about it and the rest of my hens. will they all die too?, I would be grateful of any information

So sorry to hear that you lost your hens. There are a number of chicken diseases, and only a necropsy (As you say post mortem) can verify mareks. When I had my pullet necropsy, they didn't find anything on the gross level, and had to go to the more expensive approach of growing cultures before they were certain it was Marek's.

Hopefully your flock is O.K. because some chickens are definitely resistant and do not get the disease - which was part of the point of this thread- research has shown that the B21 gene may be one indicator of resistance.

Here is a link to a Marek's fact site - where there is a collection of information and experiences with links to university sites as well if you would like to read up on it.
https://www.backyardchickens.com/a/mareks-disease-fact-site

Sorry that you didn't get an answer in January - hope your other chickens are all fine!