>So once again I ask, How do T cells distinguish foreign antigens from
>idiotypes presented by B cells? Why should the former activate and the
>latter not?
>>Ephraim Fuchs
For peptides from the idiotypic region to be presented by MHC class I or
II molecules it must a) possess the proper binding MHC binding motif and
b) have a sufficiently high binding affinity and/or be present in high
enough concentration to effectively compete with other self-peptides.
Thus, it would appear doubtful that every B-cell would effectively
present idiotypic peptides. Also, B-cells which present peptides via
class II but not class I may have an advantage in recieving added T-cell
help (possible means of autoimmunity?). Finally, it seems of very low
probability that a single, non-proliferating, naive B-cell will
encounter a cognate T-cell in the periphery.
Sincerely,
bryan fisk
