Saving Viral DNA: B Cell Mechanisms

[icakeov]

TL;DR Summary

Do B-cells "implicate" their chromosomes in the "antibody production" processes?

Hello,

I am not sure if this an odd or even an ignorant question or not, but I will give it a try.

I understand that the adaptive immune system "saves viral DNA" as antibodies to potentially "use" it in the future, if the antigens ever "return". I also understand that "antigens" are "virus parts", which can include "viruses' DNA".

Are the "biochemical mechanisms" in charge of creating these antibodies in B-cells in any way "implicated" or "saved" within their chromosomes? Or is it an entirely different "part"/"mechanism" of the B cell that "keeps" all these "antibody making capabilities", without any of its actual DNA being involved at all?

Many thanks for any feedback!

 

[jim mcnamara]

Some viral pathogens have RNA rather than DNA -FWIW. The immune response works usually against cell surface antigens of potential or known pathogens. The flu shots we get have virus antigens in them with names like H2N3, that are derived from dead virus particles. Not necessarily DNA or RNA.
The two flavors of viruses:
http://www.differencebetween.net/science/health/difference-between-dna-and-rna-viruses/
Actually your question confuses me. Do you want to know what B cells use to remember old enemies?
The system is not perfect - there was a paper out showing that measles infections undo the "memory" of the immune system.
Measles popular science version:
https://www.nationalgeographic.com/science/2019/03/measles-vaccine-protect-disease-immune-amnesia/
Memory B-cell, a special version of B-Cell, which is how immune "memory" is stored.
https://en.wikipedia.org/wiki/Memory_B_cell
Most of the links above have links to original research. Sometimes lots of them.

 

[BillTre]

The saving of viral DNA may be something you are confusing with the organisms in which Crispr was discovered in. These organisms uses this approach with the Crispr gene.
Read about Crispr here.

No DNA is exchanged in the adaptive immunity system.
It involves a way to generate antibodies by making mutations in only the antibody genes and the selecting for them among the antibody population.

Simplified Explanation
The way it works with the adaptive immunity system is that there are a large number of B-cells.
Among those B-cells genetic variation is created by directed self mutagenesis of specific parts of the genes that encode the antibodies. This happens such that each B-cell is different, each with a unique antibody sequence.
The presence of a antigen that sucessfully binds to an antibody molecule activates the B-cell to proliferate, thereby creating a large population of B-cells that have that particular antibody gene.
Subsequent activations can cause additional mutations that can refine the binding of the antibody molecule to the antigen as well as further promoting proliferation.
After an infection is over, there are left over B-cells that can still make antibodies for the now defeated infection.
These left over B-cells are the adaptive immune systems memory.
Wikipedia on the adaptive immunity system.

 

[icakeov]

Thank you for your responses!

I was mainly wondering how it is that living systems haven't developed a way to "package" the "antibody making genes" in B-cells into some form of "chromosomes" and send them off to reproductive cells and "plug them in" so that the next generation organism would "automatically" have this "information" when it produces its B-cells to defend itself (rather than having to pass on the antibodies through through breastmilk or vaccines, or have to make one's own through novel exposures to antigens).

I was mainly wanting to confirm that no such "mechanism" exists.

I hope I am not confusing matters further, and that I know enough about this to even ask a question like this.

 

[jim mcnamara]

Probably not from the egg or sperm DNA . Meiosis removes methylation changes to maternal DNA - the effects of environment, called epigenetics. So those changes are not preserved into the next generation. There is on-going debate about some aspects of this, however

Consider passive immunity, which is well known.

One way is through breast feeding - https://www.ncbi.nlm.nih.gov/pubmed/9892025

Another way is across the placenta from Mom to fetus.

Naturally acquired passive immunity provided during pregnancy... In humans, maternal antibodies (MatAb) are passed through the placenta to the fetus by an FcRn receptor on placental cells.

-- https://en.wikipedia.org/wiki/Passive_immunity

DNA transfer is not involved in preserving immunity memory AFAIK. @Ygggdrasil may know more.

 

[Ygggdrasil]

I was mainly wondering how it is that living systems haven't developed a way to "package" the "antibody making genes" in B-cells into some form of "chromosomes" and send them off to reproductive cells and "plug them in" so that the next generation organism would "automatically" have this "information" when it produces its B-cells to defend itself (rather than having to pass on the antibodies through through breastmilk or vaccines, or have to make one's own through novel exposures to antigens).

I was mainly wanting to confirm that no such "mechanism" exists.

No such mechanism exists. In fact, such a mechanism would be very detrimental.

All antibodies are produced from the same set of three immunoglobulin genes. In germ cells, these genes have many variant regions. As immune cells develop pre-B and pre-T cells will recombine these variant regions within the immunoglobulin genes and each resulting B or T cell will produce a unique antibody. Because this process occurs in many individual pre-B and pre-T cells, this process generates a huge diversity of antibodies throughout the body, allowing the immune system to recognize a wide variety of foreign antigens. In this way, just three immunoglobulin genes in the genome allow the body to make up to 300 billion different unique antibodies.

If the body were to swap the pre-recombined immunoglobulin genes found in germ cells with a recombined immunoglobulin genes from a mature B or T cell, then the body would only be able to produce that one form of antibody. The child resulting from that germ cell would certainly have pre-existing immunity to that one antigen, but this immunity would come at the cost of being able to develop antibodies to any other antigen.

For more information see: https://en.wikipedia.org/wiki/V(D)J_recombination

 

[icakeov]

Incredibly helpful, thank you so much!

On that note, I'm coming to a completion of a project that I have been working on for the past five years about cultures and societies, which was the primary reason that brought me here with all these "left field" questions.

I am planning to include this forum in the "thank you" section and I wanted to thank in particular @BillTre, @jim mcnamara and @Ygggdrasil for all the incredible feedback you've given me in the past few years. I would ideally like to use your actual names and titles rather than our account handles, if you are ok with that. What would be the best way to get that from you? Does the forum have a direct "messaging" option perhaps?

Again, thank you for all the amazing feedback for over a hundred questions I must have asked.

 

[BillTre]

Hi @icakeov,

You can contact people individually by clicking the envelope icon, third from the right at the top of the PF page:

Personally I have very much enjoyed your questions and am pretty sure others share this opinion.
They often raise points that are fun to consider and discuss.

I will send you a message with my info and it which will ding your attention to the messaging system.