Dr M.R. Clark (mrc7 at cus.cam.ac.uk) wrote:
: I accept fully that the logical way out of this is to say that a naive B-cell
: presents for tolerance. However what about activated B-cells undergoing somatic
: hypermutation. Experimental evidence shows us that activated B-cells make
: highly efficient antigen presenters. So how do you deal with altered
: specificity
: and idiotype during hypermutation?
The solution that Polly Matzinger and I have arrived at is that both
resting and activated B cells are tolerogenic APCs for naive but not
memory T cells. We believe that all experiments showing activated B
cells as good APCs used responder T cells that contain some memory cells
(even from T cell receptor transgenic mice).
By not allowing naive T cells to become activated by antigens presented
by B cells, the idiotype presentation problem is avoided.
Ephraim Fuchs
ejf at welchink.welch.jhu.edu
