Why are there ugly people?

Correct

Okay

 

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to Sancdkey;

It seems the imune system has:

phagocytes and two type of lymphocytes (T & B cells), produced in bone marrow at about 1 million per second rate! (All are in the "white blood cell" class.)

The phagocytes have two major divisions: "neutrophils" & "macrophages" the later being the "bigger tough guys" (neutrophils only eat about 25 bacteria in a couple of days and dies but the macrophages eat hundreds and live about a week or so). Normally body marrow makes about 100 billion phagocyte per day but when infected five times more.

The T-cells have three major divisions: "helper" "suppressor" & "killer"

Germs have "antigens," I believe exposed on their surface or "skin" and the antigens of each disease (germ type) are very different, with a lot of variation even with in one disease, but in an infection, one particular antigen is being produced in great quantity as the germs multiply.

The cells of the body have "MHC" molecules on their outsides that server as "body idenity tags" (so imune system will not attack the body's cells, except when this goes wrong in "auto-imune diseases.")
The MHC have a second duty: If the cell they are on has been infected. Then they (presumabably by inside the cell mechanism not described in Awake article) get and hold a piece of the germ antigen for the lymphocytes to try to "mate" or "fit to" and stay attached to the MHC via that piece of antigen.

There are typically 10^11 different type (shape) "hooks" on T-cells circulating in the blood (only one "hook" per cell) so despite the fact body has never seen the piece of antigen being held up by the MHC of infected cell before, there will be some T-cells that fit it well enought to latch on, but they are too few to wipe out all the germs so these must be replicated in quantity. That is where the "helper" T-cells play importnt role, and why AIDs is so devistating (It attacks the helper T-cells effectively knocking out the imune system.)

Here my Awake ref is not too clear: I gather that only the "latched on" Helper T-cells make the proteins called lymphokines and some how these proteins help all three types of T-cells when in the thymus (I was confused when recalling the thyroid) learn how to make new? or adapt? their "hooks" to be the shape that fits well the germ antigen displayed by the MHCs. Actually these replicated hooks are not exact copies, so some fit even better (and some worse of course). The "better hooks" of course grab hold of not yet occupied pieces of germ antigen held up by the MHCs causings slight different verions of the protein lymphokines to be made, so the next generation is better able to grab hold of the displayed antigen pieces - It is really Darwin evolution in a few hours "intelligent designing" at work! (but of course my Jehovahs Witness "Awake" booklet does not mention that!

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I will stop here and ask two questions:

(1)What good (to the germ) is served by placing antigens on its skin? Must be some very strong benefit as it is like walking around in shooting gallery with a target on your back.

(2) Can you go into more detail about how the lymphokines and thymus etc greatly increase the population of "crude hooks" of the "first generation"

I understand well how Darwin selection can repeat the process to make very good hooks in only a few dozen generations, so just tell how the few of the 10^11 that happen to fit initially get copied. I.e. I understand that once they have been refined by Darwin and thymus etc and exist in great numbers, you are now imune to that particular bacterial disease, even if the next time it invades its antigens are a little bit different.

I also understand that viruses are smarter than bacteria. - Not only do they get some other cell to do all the work of replicating, but they have DNR (or RNA?) sections designed to possibly be drastically different each generation so as to better "duck" the imune system and antibiotics.

 

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(1)What good (to the germ) is served by placing antigens on its skin? Must be some very strong benefit as it is like walking around in shooting gallery with a target on your back

An antigen is a substance that "provokes" an immune response.

An antigen can be

1. exogenous : i.e. they enter the body from outside. they may be inhaled (like pollen) or ingested (e.g. in the case of people with allergy to shellfish, a shellfish is an antigen) or taken by injection (e.g. some people are allergic to drugs)

2. endogenous: i.e they are produced inside the body. e.g. a virus or bacteria invades a cell and releases or makes certain proteins or polysaccharides which are processed by the cell and presented on the cell surface by MHC molecules. Some viruses can "fool" the T-cells so they are not recognised. Another source of endogenous antigens are tumor cells which produce certain tumor specific antigens as part of their "normal" processing

See the germ or bacteria do not carry the antigens; the antigens are "normal" proteins or polysaccharides for them. However they are "foreign" for us and are recognised and destroyed by the T cells.

 

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(2) Can you go into more detail about how the lymphokines and thymus etc greatly increase the population of "crude hooks" of the "first generation"


Just like the MHC molecules T cell receptors ( which bind to the antigen presented by the MHC) also have alpha and beta domains. These domains are highly variable and result in the production of millions of different T cells with different TCRs, so that the body can respond to virtually any invader.

 

Thanks for the information but it does not Even come close to answering my question: What value are antigens TO A GERM?

 

They are not antigens to the germ (bacteria or virus); they are proteins or polysaccharides that are part of their structure or processing; but since we are not germs we don't have those proteins or polysaccharides so they are antigens to us.

 

Ok that is close to my question. I have never been confused thinking the things that are antigens to humans were antigen to the germ etc. I had and still do, (perhaps wrongly) the idea that antigens were exterior parts of germs, etc. What happens when a disease bacteria enter inot a human cell? Does or does not it remain "intact"? I.e. are its "internal parts" exposed to the agents in the cell?

Since there is a "war" going on and bacteria can mutate etc. why do they not develope a exterior made of only human proteins and polsaccharieds?

I had the idea, now beging to understand wrong that just as human cells have MHC external marker, so did bactria but their external markers were of course not human ones. NOw I think you are saying (in answer to my question: "No, antigens are not special external markers but just the basic proteins, polsaccharieds, fats, and etc. than ARE the bacteia." -is this correct?

Even if it is true, I would think that after all this evolutionary time most bacteria that attack man would now be made of only human proteins, polsaccharieds, fats, and etc. Why not?

Perhaps the answer is that there is no such thing as human proteins, polsaccharieds, fats, and etc. instead there is Billy T proteins, polsaccharieds, fats, and etc. and Samcdkey proteins, polsaccharieds, fats, and etc. which are entirely different from the Billy T ones. Perhaps that is what transplant rejection is all about? Am I getting closer?

 

The reason why we get "infected" is after entering our cells, they either release toxins (bacteria) or they use our cellular machinery to duplicate and multiply (viruses); in either case there are non-self products formed, which are recognised by our immune system as foreign.

Sometimes they can "hide" or they can compromise our immunity (like AIDS, cancer) these are the diseases for which there is no cure.

MHC proteins are made by a region of the humann genome with over 100 genes, too complex for a bacteria or virus. MHC proteins are present only in vertebrates.

Then they would not need us to multiply or survive.

There are individual differences and a lot of variability, and some people are difficult to match for transplants, but the complexity is due to diversity. There are still commom proteins, e.g. if you have surgery, you can type your blood group, find a matching donor and use his blood without any ill-effects.

Note: we also have some "good" bacteria which live in our intestine and help us to digest and metabolise nutrients.
http://en.wikipedia.org/wiki/Intestinal_flora

 

Why are there stupid people?

Because in any comparison someone has to come out the loser.

 

Depends on the frame of reference you use for comparison; and as you know, lowly females like me always look for redeeming qualities, no matter how far-fetched the likelihood.

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I'm sorry, but my only fault is that I have no redeeming qualities.

 

that's nice. lump them all into one neat little pile.

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Come now Oli, no false modesty here, your only fault?

 

To make me feel better about myself.

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You're absolutely correct, Saiyyadati, I'm too modest as well.

 

Haqqan?

 

Aiwa. Rubbama.

 

Hal tatakallamu al-logha alingleziya?

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I KNEW you were going to do that.

 

Sigh! I've become too predictable....

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Maalesh, Ya Sheikh.