Prevention of adjuvant arthritis in rats by a nonapeptide from the 65‐kD mycobacterial heat shock protein: specificity and mechanism

Abstract

In a previous study we have shown that Lewis rats were completely protected from adjuvant arthritis by pretreatment with a nonapeptide (residues 180–188) of the 65‐kD mycobacterial heat shock protein. Here we address questions of specificity and mechanism(s) of protection. We demonstrate that complete protection against adjuvant arthritis can only be achieved by pre‐immunization with the nonapeptide, while pretreatment with either the octapeptide (residues 181–188) of the 65‐kD heat shock protein or unrelated immunogenic peptides failed to affect adjuvant arthritis. Interestingly, pretreatment with the nonapeptide of the 65‐kD heat shock protein did not protect Lewis rats from type II collagen‐induced arthritis. These results demonstrate that protection is both epitope and disease specific. Co‐injection of the nonapeptide with mycobacterial antigen even at a weight ratio of 5:1 (nonapeptide: mycobacteria) failed to influence the disease, suggesting that the role of the nonapeptide is not as a ‘blocking peptide’. T cells from rats immunized with nonapeptide respond to the nonapeptide as well as to mycobactcria in vitro, and adoptively transfer protection to naive recipients. The data indicate that the nonapcptide‐induced protection may result from a T cell mediated specific suppression. Copyright © 1992, Wiley Blackwell. All rights reserved