William T. Lee
leew at wadsworth.org
Mon Mar 6 08:49:44 EST 1995
In article <3jcjea$grs at newsbf02.news.aol.com>, fniner at aol.com (FNINER)
>The Seattle group showed in 1993, I believe, that the CD28 mediated
>stimulation is NOT essential for superantigen-mediated T-cell
>expansion/proliferation. They used CTLA-4Ig as a B7-directed inhibitor
>and saw no effect on Superantigen-induced IL-2 synthesis or
> Given opportunity, CD28 stimulation may augment the existing
>superantigen-induced response but its participation is not obligatorily
>required as some people would have us believe.
This might be an interesting topic for discussion. A recent paper by
Blankson and Morse (Cell. Immunol. 157:306-312. 1994) indicated the
oppostie. In their system they used cells from a TcR Tg mouse and
compared the response to both peptide and SEB. The APC were (I can't
remember off the top of my head whether it was a co-culture or a double
transfectant with class II) B7-transfected fibroblasts. Only in the
presence of B7 was proliferation to either Ag or sAg seen.
In my own experiments using either normal or Tg T cells, the inclusion of
Fab anti-CD28 blocks the response to both Ag or SEB by about 60-70%.
This is in line with published inhibitory affects of Fab anti-CD28 or
CTLA4-Ig, in in vitro assays.
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