t and b cells (1 Viewer)

[ImNuMbErOnE]

What about them???

 

[vivacious]

what is their function, are they just markers?

 

[arls]

Originally posted by vivacious
what is their function, are they just markers?

my notes arent on the computer and itl take yrs to type them up but look up a text book or check out the answers to dot points on the charles sturt site http://hsc.csu.edu.au/


this is quite important for the topic...

 

[psycho_mushy]

T and B cells:

T cells have receptors on thier surface that match the structure of an anitugen on an infected cell or on a antigen

B cells produce antibodies that have a shape that fits with an antigen

 

[tempco]

Originally posted by psycho_mushy
B cells produce antibodies that have a shape that fits with an antigen

Don't B cells also have receptors on their surface? I know that they're activated by Helper T cells, when they secrete interleukin, but I'm not sure if they can be activated by free antigens.

 

[psycho_mushy]

nono.. of coruse they can't be activated freely!I thought u knew what i meant!

 

[tempco]

Meh... Ok fine, Helper T cells are activated by antigens that are displayed by macrophages. B cells are activated by Helper T cells when they secrete certain chemicals. That correct?

 

[*~Dazed~*]

B cells are lymphocytes and are STIMULATED, by B cells to produce plasma cells to become an antibody cell...
T cells however are lymphocytes that can destroy the antigen themselves....unlike b cells they dont produce and antibody, but secrete substances that either directly destory the pathogen or stimulate the activity of phagocytes (which is phagocytosis in the 2nd line of defence)

there are 4 types of t cells...
killer, helper, suppresor and memory which kind of speak for themselves.... memory retain the ability to recognise an antigen in the future if it appears again and thus are more efficient in killing it or dealing with it in whatever way is most appropriate

there are 2 mechanisms whereby t and b cells interact
the first is where an antigen stimulates the tcell, which lets off a soluble factor which in turn stimulate the bcell and makes it aware of the antigen.... it then forms a plasma cell and becomes a functioning antibody producing cell

the 2nd is where the b cell gets stimulated by the antigen and makes the t cell aware of it by direct contact.... rather than a soluble factor.... the rest of the process is the same

hope that helped... its off the top of my head so it might not make any sense

 

[tempco]

Originally posted by *~Dazed~*
the 2nd is where the b cell gets stimulated by the antigen and makes the t cell aware of it by direct contact.... rather than a soluble factor.... the rest of the process is the same

So B cells are stimulated by free antigens? or are these antigens presented by macrophages?

 

[*~Dazed~*]

hmmm im not sure about that... sorry... all i know is that in both cases the b cell is stimulated by the antigen in the same way... the difference comes in the way that the b cell lets the t cell know... 1 is by contact one is by a soluble factor...
im sorry....
im not even sure what macrophages are...

 

[tempco]

Just in case you wanted to know:

Macrophages are phagocytes that are responsible for phagocytosis (engulfing of antigens). When the antigen is ingested by the macrophage, it is joined with a lysosome, which contains the enzyme lysozyme. The antigen is broken down by this enzyme and expelled from the macrophage.

 

[*~Dazed~*]

ahhh ok thank you thank you.... yeah i know about phagocytosis... hmm i didnt realise that macrophages were invoved.... never heard of lysozyme's though... ahh well shit happens..
at least bio is a subject that any last minute info you hear does actually help! unlike things like business and english which can confused you

 

[tempco]

Yep so true! But you just gotta remember lysozyme = enzyme... breaks down antigens.. that's all.