th0-3 cells

[chan4 at fas.harvard.edu]

In <ralph.1146355927D at news.arizona.edu>, ralph at ccit.arizona.edu (Ralph M Bernstein) writes:
>chan wrote:
>
>>In article <3kolh2$b8k at styx.uwa.edu.au> Alec Redwood,
>>aredwood at uniwa.uwa.edu.au writes:
>>>: Can anyone tell me about TH3 cells and/or direct me to an article. 
>>
>>
>>These cells were coined by those working in EAE model.  They found high
>>TGFb producers when fed MBF orally.  The cells did not fit into neat TH1
>>or TH2 so they coined the term.  I think this is bunk.  There is no clear
>>Th1 or Th2 anyway.  These cells are far more versatile than those in
> ^^^^^^^^^^
>
>>Huh?!?
>
>>CD4+ TH1 cells have decidedly different cytokine production than CD4+TH2 
>>cells.  There is evidence that one cell type can downregulate the other 
>>cell type (or phenotype, if you think they are the same cell).  However, 
>>it's interesting to note that Fas Ligand-mediated cytoxicity/apoptosis is 
>>mediated by TH1 CD4+ cells and not the TH2 CD4+ cells (This doesn't 
>>exclude the CD8+ cells from carrying on a non-calcium 
>>dependent/Fas-dependent mechanism of lysis of target cells, of course.) 
>
>Derek,
>    ok, i think i kind of agree with the ambiguities that David was
>mentioning.  you say huh, but what about the inconsistancies associated with
>th1-th2 cells? 



like in the _same_ disease model one lab getting th1 but
>another (competing) lab getting th2 type?

Hmm..that's pretty interesting...  Curious...which two labs?  I'm not too
much of a mouse immunologist, butif you point me to those papers, I'd be
happy to check 'em out.


it's neat to note the FAS 
>connection, but has anyone else done that and reproducably gotten a th1
>phenotype?  i mean, it does make sense that the killer enhancing th's would

Well it's been shown that you can actually have a CD4 response to a cell, but
non-lysis of the target cell, and this is attributed to a non-FasL mediated 
response.  Apparently, this "wrong response" doesn't enable the disease to be
properly "killed" (for lack of a better word).

>"kill" via fas and gld, but has anyone else show it?  _also_, is any one
>getting closer to some sort of marker for the th's?  (other than the
>suppoesed cytokine differences)

I agree...I think that currently, cytokine differences are what everyone's looking
at to determine whether there is a Th1 or a Th2 response.  It has been shown 
that the CD4+ cells which can cause apoptosis of target cells by a fas-
dependent mechanism _do_ "fit" with the Th1 phenotype in terms of cytokine
production.


>    again, i think that the th1 cth2 "paradigm" has a way to go to be really
>accepted as undisputable.  just call me a th1-th2 agnostic-i'm just waiting
>for some real good proof.
>
Regards,

Derek


Derek V. Chan
chan4 at fas.harvard.edu
dvchan at netcom.com