The Peptidome of Behçet's Disease–Associated HLA–B*51:01 Includes Two Subpeptidomes Differentially Shaped by Endoplasmic Reticulum Aminopeptidase 1

Abstract

ERAP-1 has a significant influence on the B*51:01 peptidome and its affinity. This influence is based on very distinct effects on the 2 subpeptidomes, whereby only peptides in the subpeptidome with Ala at position 2 are extensively destroyed, except when their position 1 residues are ERAP-1 resistant. This pattern provides a mechanism for the epistatic association of ERAP-1 and B*51:01 in Behçet's disease.