IDENTIFICATION AND CHARACTERIZATION A TOLEROGENIC T-CELL DETERMINANT WITHIN RESIDUES 181-209 OF CHICK TYPE-II COLLAGEN

The murine model of collagen-induced arthritis is characterized by the development of an immune response against joint cartilage. Arthritis can be significantly suppressed by the administration of type II colla gen (CII) or one of the CNBr peptides, CB11 (CII 124-402) as a tolerog en prior to immunization. We have previously shown that two synthetic peptides, representing sequences CII 260-270 and CII 181-209, are effe ctive tolerogens. In this paper, we now characterize the T cell determ inant with CII 181-209. A series of synthetic peptides overlapping CII 181-209 and analogs of chick CII 181-209 containing site-directed ami no acid substitutions was developed and cultured with T cells from DBA /1 mice immunized with CII. Supernatants were collected and analyzed f or the presence of the T cell lymphokine IFN-gamma. These data indicat e the critical T cell determinant to be located within CII 190-200. Th is conclusion is further supported by the observation that an unodecap eptide representing CII 190-200 was just as effective as CII 181-209 i n suppressing arthritis and anti-CII antibody response when tested as a tolerogen. Analogs containing single amino acid substitutions at res idues 191, 194, 197, 198, or 200 were significantly less effective in inducing T cell responses. Each of these peptide analogs was then give n as neonatal tolerogens to DBA/1 mice. Mice were subsequently immuniz ed and observed for the development of arthritis. These studies identi fied residues 194, 197, 198, and 200, and probably residue 191, as cri tical for tolerance and the suppression of arthritis. Elucidation of t he fine structures of T cell determinants which are critical for suppr ession of arthritis should allow these techniques to be used for devel oping specific immunotherapeutic approaches to autoimmune arthritis. ( C) 1995 Academic Press, Inc.