Multiple class I motifs revealed by sequencing naturally processed peptides eluted from rat T cell MHC molecules

Abstract

Class I major histocompatibility complex (MHC) molecules interact with a diverse array of self and foreign peptides. Displayed on the cell surface, the class I/peptide complex provides an extracellular indication of the intracellular milieu. We have characterized the Lewis rat Vbeta8.2+ T cell hybridoma C14/BW12-12A1 by FACS analysis and have used immunoaffinity chromatography to purify class I molecules from these cells. Peptides eluted from the class I molecules have been fractionated by HPLC and sequenced. Self-peptide mixtures indicate two distinct peptide motifs, suggesting the possibility of multiple class I loci. The majority of the naturally processed peptide ligands were nonamers. Naturally processed peptide ligands fitting the first motif contained a hydrophobic leucine anchor residue at position three and a carboxyl-terminal serine anchor residue. A second motif was characterized by a tyrosine or phenylalanine residue at position three and a phenylalanine or isoleucine carboxyl-terminal residue. Four peptides derived from the Vbeta8.2 T cell receptor have sequences that fit these motifs, providing a mechanistic explanation for their immunoregulatory role. Identification of these class I peptide binding motifs will be useful for predicting potential CTL epitopes in studies on autoimmunity, immunoregulation and transplantation in the Lewis rat.

Peptide length preferences for rat and mouse MHC class I molecules using random peptide libraries

“…Both showed a C-terminal aromatic/hydrophobic preference [20], agreeing with the C-terminal preference for TAP-B. RT1-A a , which is genetically associated with the more permissive TAP-A transporter, was found to have an arginine preference at the C terminus [15], whereas the peptide motif of RT1-A l revealed a C terminus with an aromatic/hydrophobic preference [9,21,22]. The allelic MHC class I-TAP association, as seen in rats, cannot be explained solely by the C-terminal peptide repertoire transported by the two forms of rat TAP and the specificity of the MHC class Ia/C-terminal peptide preference since, by this argument, RT1-A l would be expected to be associated with the TAP-B form of the transporter.…”

A Structurally Altered d,l-Amino Acid TCRα Transmembrane Peptide Interacts with the TCRα and Inhibits T-Cell Activation in Vitro and in an Animal Model

“…These results further support specific interaction of 2D-CP with the TCR molecule. The A2b T-cell line used in our studies (and rat T-cells in general) expresses high levels of MHC class I molecules (45,46); indeed a comparison of the MHC class I and TCR expression has shown that TCR and MHC I molecules are expressed at similar levels by rat T-cells using the same antibodies as in the co-immunoprecipitation experiment (47). Moreover, the procedure for the immunoprecipitation of MHC class I molecules with the Ox18 antibody has been used in our laboratory to determine the binding motifs of MHC class I rat molecules.…”

Effects of vaccination with T cell receptor peptides: Epitope switching to a possible disease‐protective determinant of myelin basic protein that is cross‐reactive with a TCR BV peptide

“…19±20 From these eluted peptides, we identi®ed two distinct nonamer peptide motifs, including XXLXXXXXS (pattern 1) and XXYXXXXXF (pattern 2), thought to represent general patterns found in peptides that preferentially bind to two dierent RT-1B MHC class I molecules. 20 Interestingly, the BV8S2-42±50 peptide, HGLRLIHYS, contained MHC binding anchor residues identical to those found in pattern 1. Moreover, three BV8S2 peptides from the 71±95 region were identi®ed that contained anchor residues similar to those found in pattern 2.…”

“…Recently, we characterized both rat and mouse MHC class I bound peptides eluted from rat‐mouse hybridomas obtained by fusing Gp‐MBP‐72–89‐specific T cells with the mouse BW‐5147 fusion partner 19 , 20 . From these eluted peptides, we identified two distinct nonamer peptide motifs, including XX L XXXXX S (pattern 1) and XX Y XXXXX F (pattern 2), thought to represent general patterns found in peptides that preferentially bind to two different RT‐1B MHC class I molecules 20 . Interestingly, the BV8S2‐42–50 peptide, HG L RLIHY S , contained MHC binding anchor residues identical to those found in pattern 1.…”