'Genetics' of immune cells?

casebro

Penultimate Amazing
casebro
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Like mast cells. First exposure to an allergen does not trigger any reaction. But it does sensitize the cells. Next exposure triggers the immune reaction. In the mean time, those first cells have died off, and been replaced by new cells made in the bone marrow. Hence forth, all mast cells made by the marrow are sensitive to those same allergens.

So I'm thinking that the original exposure led to a genetic change in the marrow, since now it is making cells with different traits.

BUT, we supposedly don't change our DNA to suit current life problems. IE: generations of shaving won't bring about a dna change to beardless males.

Explain? How does the marrow make new cells with new senstivities?
 
I can't claim to understand anywhere near enough to be able to answer your question, but I can say this much with complete confidence: The situation is not anywhere near as simple as you suggest. For one thing, the immune system exhibits characteristics of an evolutionary process within an evolutionary process, with lineages of various types of cells essentially competing with one another. If you're interested enough to dedicate some time to the subject, I can recommend a book, "Immunology and Evolution of Infectious Disease", by Steven A. Frank. You can view or download a full copy here:

http://stevefrank.org/antiVar/antiVar.html
 
It is complex but centres around genetic recombination (shuffling) of the immunoglobulin gene family which generates antigen receptors capable of recognising 10^12 molecules. Can I ask that you read the wikipedia entry rather than me trying to explain it simply here?

http://en.wikipedia.org/wiki/Immunoglobulin_gene
 
Okay, so I did have a correct flash of insight. And, some day, science might come up with a genetic therapy to prevent auto-immune diseases, like Lupus, Rheumatoid arthritis, and allergies.

Did anybody see this article:

http://www.foxnews.com/story/0,2933,560760,00.html?test=latestnews

IBM is working on a DNA bar-code reader. It'll bring individual genetic code reading down to afffordability. Not to mention that the data base of genes-to-diseases will explode. Genetic cures for EVERYTHING!!!!
 
Just looking at you original post. The immune system at first has cells that can recognise 10^12 antigens. The immune system samples the proteins presented on the cell surface by the major histocompatibility complex, some of these are our own antigens and it's not good to make an immune response to yourself, so only antigens that are presented to the immune system in the context of confirmatory signals. Cells that recognise self antigens are not maintained and are deleted. So it's really a loss of cells from the original 10^12 library, rather than a gain of new ones.
 
casebro said:
Like mast cells. First exposure to an allergen does not trigger any reaction. But it does sensitize the cells. Next exposure triggers the immune reaction. In the mean time, those first cells have died off, and been replaced by new cells made in the bone marrow. Hence forth, all mast cells made by the marrow are sensitive to those same allergens.

So I'm thinking that the original exposure led to a genetic change in the marrow, since now it is making cells with different traits.

BUT, we supposedly don't change our DNA to suit current life problems. IE: generations of shaving won't bring about a dna change to beardless males.

Explain? How does the marrow make new cells with new senstivities?
Click to expand...

Capsid's link was best, but I think the disconnect is that there is no change in the way the marrow produces cells caused by new antigen.

The marrow keeps producing the same random mix of immune cells. These are called clonal lines. Different clonal lines will recognize different antigens. Many are deleted to stop them from responding to host tissue. ("clonal deletion")

The clonal lines that are floating around may or may not match antigen. Most will never match antigens during the host's life.

If a cell does, it is provoked to dramatically increase its population (expand the clonal line). This takes time, which is why the first exposure does not usually result in a 'specific' immune response. The antigen is typically destroyed by general immunity long before the clonal lines are ramped up.

Nevertheless, these clonal lines that have memory of an antigen are now more abundant, and the next infection will see a faster and more intense specific immunity response.

Of particular importance are the "B" cells, which are sometimes called "memory B" cells, as their function is to represent past antigen exposure.



I have worked with autoimmune disorder research in the past. I'd like to return to that, as I feel the benefits of progress in that field are great.
 
I am an immunologist. I really don't have much to add to what has already been stating so nicely by Capsid and blutoski. The genetics really don't change. The cells that are responding are clonal copies of earlier cells that already were making receptors that recognized the original antigen. There are also cells that don't respond, but the ones that do respond are stimulated to multiply more quickly, thus boosting their population in comparison to the non-responding cells.
 
Casebro said:
IBM is working on a DNA bar-code reader. It'll bring individual genetic code reading down to afffordability.
Click to expand...

I heard Google are developing a DNA Defragmenter / compression utility.
Get rid of all that HERV / Junk DNA. Stitch up all those broken chains.
Did you know you have 20 pounds of noncoding DNA cluttering your colon?


OK. OK. Not yet...but some day.;)
 
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