|
||
By

From the * Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical
School, Boston, Massachusetts 02115; and the We previously generated a panel of T helper cell 1 (Th1) clones specific for an encephalitogenic peptide of myelin proteolipid protein (PLP) peptide 139-151 (HSLGKWLGHPDKF)
that induces experimental autoimmune encephalomyelitis (EAE) upon adoptive transfer. In spite of the differences in their T cell receptor (TCR) gene usage, all these Th1 clones required
W144 as the primary and most critical TCR contact residue for the activation. In this study,
we determined the TCR contact residues of a panel of Th2/Th0 clones specific for the PLP
peptide 139-151 generated either by immunization with the PLP 139-151 peptide with anti-
B7-1 antibody or by immunization with an altered peptide Q144. Using alanine-substituted
peptide analogues of the native PLP peptide, we show that the Th2 clones have shifted their
primary contact residue to the NH2-terminal end of the peptide. These Th2 cells do not show
any dependence on the W144, but show a critical requirement for L141/G142 as their major
TCR contact residue. Thus, in contrast with the Th1 clones that did not proliferate to A144-substituted peptide, the Th2 clones tolerated a substitution at position 144 and proliferated to
A144 peptide. This alternative A144 reactive repertoire appears to have a critical role in the
regulation of autoimmune response to PLP 139-151 because preimmunization with A144 to
expand the L141/G142-reactive repertoire protects mice from developing EAE induced with
the native PLP 139-151 peptide. These data suggest that a balance between two different T
cell repertoires specific for same autoantigenic epitope can determine disease phenotype, i.e.,
resistance or susceptibility to an autoimmune disease.
Department of Medicine, Royal Brisbane Hospital,
University of Queensland, Herston Q4029, Australia
This article has been cited by other articles:
| TABLE OF CONTENTS |
|