Re: Anybody a biology buff? I need some info about the autoimmune response.

[Guest guest]

,

Orencia (abatacept/CTLA4-Ig) inhibits the costimulation of T cells.

One way (there are other pathways) in which a T cell becomes fully

activated is that the T cell receptor binds to the major

histocompatibility complex (MHC)/antigenic peptide complex on the

antigen presenting cell (APC) and receives a first signal AND the T

cell's CD28 protein binds to the B7 protein of the antigen-presenting

cell and receives a second signal (the costimulatory signal).

Abatacept binds to B7 protein on APCs, thus preventing them from

delivering the second signal needed to activate the T cells.

In simple terms, this means that, theoretically, abatacept works by

reducing the number of T cells that are " turned on. " Since the

activation of T cells is early in the chain of events which leads to

the inflammatory process (T cell proliferation, cytokine production, B

cell and macrophage activation, etc.) associated with RA, abatacept

works by nipping the problem in the bud, so to speak.

APCs can be many different types of cells. For example, macrophages, B

cells, and dendritic cells can be APCs. Any or all of these could

present markers found in synovial tissue.

Here are a couple of links to information which may be helpful:

http://www.fda.gov/ohrms/dockets/AC/05/slides/2005-4170S1_01_FDA-.ppt

http://www.ispub.com/ostia/index.php?xmlFilePath=journals/ijrh/vol3n1/abatacept.\

xml

http://arthritis-research.com/content/9/2/205

http://www.ncbi.nlm.nih.gov/pubmed/17977483

http://www.ncbi.nlm.nih.gov/pubmed/18292234

http://www.ncbi.nlm.nih.gov/pubmed/18163520

http://www.ncbi.nlm.nih.gov/pubmed/18239374

Not an MD

On Wed, Apr 9, 2008 at 12:08 AM, <sugafreak21@...> wrote:

> I have a degree in biology but since I have not used this degree in the

> least I am rusty on my knowledge. I have a question about the way in

> which our meds interupt or circumvent the immune response. I have

> recently been put on Orencia which I believe combats the T cells

> themselves. I'm thoroughly confused. Is this med sapossed to supress

> the antigen-presenting genes or inhibit the production of T-cells? I

> read my booklet but it doesn't even go into depth about the process.

> Also, is the antigen-presenting gene a macrophage that detects synovial

> fluid? I know this sounds dumb, but I really wish someone can explain

> this to me so I will better prepared to ask questions at the doc's

> office. Help me out RN's!!!!Please!!

[Guest guest]

Thanx .

> > I have a degree in biology but since I have not used this degree

in the

> > least I am rusty on my knowledge. I have a question about the

way in

> > which our meds interupt or circumvent the immune response. I have

> > recently been put on Orencia which I believe combats the T cells

> > themselves. I'm thoroughly confused. Is this med sapossed to

supress

> > the antigen-presenting genes or inhibit the production of T-

cells? I

> > read my booklet but it doesn't even go into depth about the

process.

> > Also, is the antigen-presenting gene a macrophage that detects

synovial

> > fluid? I know this sounds dumb, but I really wish someone can

explain

> > this to me so I will better prepared to ask questions at the doc's

> > office. Help me out RN's!!!!Please!!

>