The HLA-DRB1*03:01 ligandome is highly conserved on N- and C-terminal residues outside the peptide-binding cleft

ABSTRACT: Human CD4+ T lymphocytes play an important role in inducing potent immune responses. They are activated and stimulated by peptides presented in Major Histocompatibility Complex Class II molecules. These MHC class II molecules typically present peptides of between 12 and 20 amino acids in length. The region that interacts with the MHC molecule, designated as the binding core, is highly conserved in the residues which anchor the peptide to the molecule. In addition, as these peptides are the product of proteolytic cleavages, certain conserved residues may be expected at the N- and C-termini outside the binding core. To study whether similar conserved residues are present in different types of cells , the ligandomes of HLA-DRB1*03:01 derived from two different cell types (dendritic cells and EBV-transformed B-cells) were identified with mass spectrometry and the binding core and N- and C-terminal residues were analysed using the frequencies of the amino acids in the human proteome. Similar binding motifs were found as well as comparable conservations in the N- and C-terminal residues. Furthermore, these terminal conservations of the HLA-DRB1*03:01 ligandome were compared to the N- and C-terminal conservations of the HLA-DRB1*04:01 ligandome acquired from dendritic cells. Again, comparable conservations were evident with only minor differences. Taken all together, these analyses show that there are conservations in the terminal residues of peptides, presumably the result of the activity of proteases involved in antigen processing.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): B Cell, Dendritic Cell, Cell Culture

DISEASE(S): Disease Free

SUBMITTER: G Janssen  

LAB HEAD: Peter A van Veelen

PROVIDER: PXD014253 | Pride | 2019-09-16

REPOSITORIES: Pride