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Publication Abstract from PubMed

The mouse H13 minor histocompatibility (H) Ag, originally detected as a barrier to allograft transplants, is remarkable in that rejection is a consequence of an extremely subtle interchange, P4(Val/Ile), in a nonamer H2-D(b)-bound peptide. Moreover, H13 peptides lack the canonical P5(Asn) central anchor residue normally considered important for forming a peptide/MHC complex. To understand how these noncanonical peptide pMHC complexes form physiologically active TCR ligands, crystal structures of allelic H13 pD(b) complexes and a P5(Asn) anchored pD(b) analog were solved to high resolution. The structures show that the basis of TCRs to distinguish self from nonself H13 peptides is their ability to distinguish a single solvent-exposed methyl group. In addition, the structures demonstrate that there is no need for H13 peptides to derive any stabilization from interactions within the central C pocket to generate fully functional pMHC complexes. These results provide a structural explanation for a classical non-MHC-encoded H Ag, and they call into question the requirement for contact between anchor residues and the major MHC binding pockets in vaccine design.

How H13 histocompatibility peptides differing by a single methyl group and lacking conventional MHC binding anchor motifs determine self-nonself discrimination.,Ostrov DA, Roden MM, Shi W, Palmieri E, Christianson GJ, Mendoza L, Villaflor G, Tilley D, Shastri N, Grey H, Almo SC, Roopenian D, Nathenson SG J Immunol. 2002 Jan 1;168(1):283-9. PMID:11751972^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.