Does presentation of antigenes kill antigene source?

[Dims]

Hi!

 

And excuse my English.

 

I'v read, that some phagocytes take foreign antigenes and present them to

T-cells. But what for? If phagocyte has antigenes to present, then antigene

source is already eaten and not dangerous. Is it reasonable? It comes out,

that the role of phagocyte is to sometimes preventive eat every cell only to

check if it is bad? Is it so?

 

Or may be these phagocytes don't completely eat antigene source, but only

scrape antigenes from the source? Is it can be so? Do antigenes regenerate

on the source surface?

 

Thanx.

[scicop]

This is basic immunology, I really suggest reading a text book on the topic. The immune systems is one of the few systems that we have the most understanding on!

[Dr. Dalek]

....I'v read' date=' that some phagocytes take foreign antigenes and present them to T-cells. But what for? If phagocyte has antigenes to present, then antigene

source is already eaten and not dangerous. ......[/quote']

 

The phagocyte eats the antigen, and the organism that is the source of the antigen. However if there is one harmful microscopic organism there is usually a population. Therefore the T-cells have to mount an assault on the rest of the population.

 

............ It comes out' date=' that the role of phagocyte is to sometimes preventive eat every cell only to check if it is bad? Is it so?

[/quote']

 

No

It eats organisms marked by the immune system to be foreign. It displays the antigen so that other immune cells can recognize it and attack the source organism.

[scicop]

Jesus, this guy hasn't even read a basic introductory to immunology. If he did he would learn things such as the need to erradicate xenobiotics by the innate immunesystem and the need for the recruitment of the adaptive immune system to combat the invading pathogens!

 

Dude, do a google search, type in MHC I and II. Type in Toll receptors, Type in Cytokines, even T-Cells, B-cells. This is basic information that you can find in a Biology 101 text book.

[zyncod]

Scicop, I think you meant Toll-like receptors, since I assume that he's not interested in drosophilid immunity. I really think that they should put old editions of textbooks online for free (in this case, the first or second edition of Janeway), because it is actually really difficult to get basic information online.

 

Completely off-topic, I'm actually kind of interested in what you do for the NYPD, given your apparent background.

[scicop]

Scicop' date=' I think you meant Toll-like receptors, since I assume that he's not interested in drosophilid immunity. I really think that they should put old editions of textbooks online for free (in this case, the first or second edition of Janeway), because it is actually really difficult to get basic information online.

 

Completely off-topic, I'm actually kind of interested in what you do for the NYPD, given your apparent background.[/quote']

 

You are right zyncod...TLR's!! Cool receptors when you think about it.

 

As for the NYPD, I'm just a regular police officer (relatively new, just a few months) assigned to an investigations unit. Can't disclose my specific unit, but there is alot of science-based consulting that is involved with my job. There is a need for scientifically trained police officers to help translate science information to the criminal justice world, so I invite others to pursue this path, it has been interesting, especially after 9.11. What I can say is that I am not CSI! (CSU in NYPD) I don't wear sunglasses and I don't ever go to any crime scenes! There are no CSIs per se, rather most are detectives (rank you get after 18 months assigned to an investigations unit)

 

The NYPD can be a crappy department to work for, but if you have the right background you can get into some awesome jobs. Due to the crappy-ness and low pay, I am looking for other options, such as working as a military scientist. I'm just using this as a stepping stone to something else.

 

Its definately a path to explore, let me know if you have any other questions.

[Immunologist]

Hello Dims,

 

First, part of Scicop says is true, these are notions you would easily get in a basic immunology book, but there is no need to be as agressive as he is.

 

Second, Dr. Dalek provided come clues, but he is not absolutly right...

 

So third, here goes my answer: Phagocytes are usually wandering around in different tissues and engulf by phagocytosis many things, self and non-self. Once it is said, we must conclude that they also "eat" things that are not dangerous! So your idea that they are eating in a preventive manner is not absolutly wrong, but inexact. For example, they are eating dead cells from the body to remove them from the tissue. But in this case, as it is not a danger signal, there is antigen presentation, but no activation of the immune response against it!

 

How does it happens? Well antigen presenting cells (APCs) have different cell receptors, commonly reffered as "Pattern Recognition Receptors" PRRs. These receptors include the Toll-Like Receptors (TLRs) that the others discussed before. These receptors do recognize non-self and therefore "activate" the phagocyte. In the case of a self molecule, it is phagocytosed, but not recognized by these receptors, so the APC does not get activated.

 

What is activation? Activation ensures that the APC will be presenting the antigen (Ag) to the Tcells concurently with a second signal (co-signal). This co-signal is NECESSARY for activation of the immune response, without it, Tcells will not respond.

 

Think this should be clear. So yes the engulfed pathogen (or other) is killed, but it is important that Ag presentation occurs so that the immune system is made aware of the presence of this pathogen, because all chances are that others are present!

 

Is it ok

[Steph]

Pretty good answer...

 

here is a link to immunobiology 5th edition (pubmed) and i think it's free.

 

http://www.ncbi.nlm.nih.gov/books/bv.fcgi?call=bv.View..ShowTOC&rid=imm.TOC&depth=10