PMID- 31619516 OWN - NLM STAT- MEDLINE DCOM- 20200622 LR - 20240210 IS - 1083-351X (Electronic) IS - 0021-9258 (Print) IS - 0021-9258 (Linking) VI - 294 IP - 52 DP - 2019 Dec 27 TI - Human leukocyte antigen (HLA) class II peptide flanking residues tune the immunogenicity of a human tumor-derived epitope. PG - 20246-20258 LID - 10.1074/jbc.RA119.009437 [doi] AB - CD4(+) T-cells recognize peptide antigens, in the context of human leukocyte antigen (HLA) class II molecules (HLA-II), which through peptide-flanking residues (PFRs) can extend beyond the limits of the HLA binding. The role of the PFRs during antigen recognition is not fully understood; however, recent studies have indicated that these regions can influence T-cell receptor (TCR) affinity and pHLA-II stability. Here, using various biochemical approaches including peptide sensitivity ELISA and ELISpot assays, peptide-binding assays and HLA-II tetramer staining, we focused on CD4(+) T-cell responses against a tumor antigen, 5T4 oncofetal trophoblast glycoprotein (5T4), which have been associated with improved control of colorectal cancer. Despite their weak TCR-binding affinity, we found that anti-5T4 CD4(+) T-cells are polyfunctional and that their PFRs are essential for TCR recognition of the core bound nonamer. The high-resolution (1.95 A) crystal structure of HLA-DR1 presenting the immunodominant 20-mer peptide 5T4(111-130), combined with molecular dynamic simulations, revealed how PFRs explore the HLA-proximal space to contribute to antigen reactivity. These findings advance our understanding of what constitutes an HLA-II epitope and indicate that PFRs can tune weak affinity TCR-pHLA-II interactions. CI - (c) 2019 MacLachlan et al. FAU - MacLachlan, Bruce J AU - MacLachlan BJ AUID- ORCID: 0000-0002-2685-2733 AD - Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University, Cardiff CF14 4XN, United Kingdom. FAU - Dolton, Garry AU - Dolton G AD - Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University, Cardiff CF14 4XN, United Kingdom. FAU - Papakyriakou, Athanasios AU - Papakyriakou A AUID- ORCID: 0000-0003-3931-6232 AD - Institute of Biosciences and Applications, NCSR "Demokritos," Agia Paraskevi, 15341 Athens, Greece. FAU - Greenshields-Watson, Alexander AU - Greenshields-Watson A AUID- ORCID: 0000-0002-8740-9823 AD - Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University, Cardiff CF14 4XN, United Kingdom. FAU - Mason, Georgina H AU - Mason GH AD - Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University, Cardiff CF14 4XN, United Kingdom. FAU - Schauenburg, Andrea AU - Schauenburg A AUID- ORCID: 0000-0003-3561-2077 AD - Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University, Cardiff CF14 4XN, United Kingdom. FAU - Besneux, Matthieu AU - Besneux M AD - Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University, Cardiff CF14 4XN, United Kingdom. FAU - Szomolay, Barbara AU - Szomolay B AUID- ORCID: 0000-0002-5375-5533 AD - Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University, Cardiff CF14 4XN, United Kingdom. FAU - Elliott, Tim AU - Elliott T AUID- ORCID: 0000-0003-1097-0222 AD - Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom. AD - Centre for Cancer Immunology, University of Southampton, Faculty of Medicine, University Hospital, Southampton SO16 6YD, United Kingdom. FAU - Sewell, Andrew K AU - Sewell AK AUID- ORCID: 0000-0003-3194-3135 AD - Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University, Cardiff CF14 4XN, United Kingdom. FAU - Gallimore, Awen AU - Gallimore A AUID- ORCID: 0000-0001-6675-7004 AD - Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University, Cardiff CF14 4XN, United Kingdom. FAU - Rizkallah, Pierre AU - Rizkallah P AUID- ORCID: 0000-0002-9290-0369 AD - Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University, Cardiff CF14 4XN, United Kingdom. FAU - Cole, David K AU - Cole DK AUID- ORCID: 0000-0003-0028-9396 AD - Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University, Cardiff CF14 4XN, United Kingdom. FAU - Godkin, Andrew AU - Godkin A AUID- ORCID: 0000-0002-1910-7567 AD - Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University, Cardiff CF14 4XN, United Kingdom GodkinAJ@cardiff.ac.uk. AD - Department of Gastroenterology and Hepatology, University Hospital of Wales, CF14 4XN Cardiff, United Kingdom. LA - eng SI - PDB/4CNM SI - PDB/6HBY GR - WT_/Wellcome Trust/United Kingdom GR - 16997/CRUK_/Cancer Research UK/United Kingdom GR - 21200/CRUK_/Cancer Research UK/United Kingdom PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20191016 PL - United States TA - J Biol Chem JT - The Journal of biological chemistry JID - 2985121R RN - 0 (Epitopes) RN - 0 (HLA-DR1 Antigen) RN - 0 (Membrane Glycoproteins) RN - 0 (Peptides) RN - 0 (trophoblastic glycoprotein 5T4, human) SB - IM MH - Amino Acid Sequence MH - Binding Sites MH - CD4-Positive T-Lymphocytes/cytology/immunology/metabolism MH - Colorectal Neoplasms/metabolism/pathology MH - Crystallography, X-Ray MH - Epitopes/chemistry/*immunology/metabolism MH - HLA-DR1 Antigen/chemistry/immunology/*metabolism MH - Humans MH - Membrane Glycoproteins/chemistry/metabolism MH - Molecular Dynamics Simulation MH - Peptides/chemistry/metabolism MH - Protein Binding MH - Protein Structure, Secondary MH - Protein Structure, Tertiary PMC - PMC6937582 OTO - NOTNLM OT - T-cell biology OT - antigen presentation OT - antigen recognition OT - crystallography OT - molecular dynamics OT - peptide flanking residues OT - structure-function OT - tumor immunology COIS- The authors declare that they have no conflicts of interest with the contents of this article EDAT- 2019/10/18 06:00 MHDA- 2020/06/23 06:00 PMCR- 2019/10/16 CRDT- 2019/10/18 06:00 PHST- 2019/06/09 00:00 [received] PHST- 2019/09/18 00:00 [revised] PHST- 2019/10/18 06:00 [pubmed] PHST- 2020/06/23 06:00 [medline] PHST- 2019/10/18 06:00 [entrez] PHST- 2019/10/16 00:00 [pmc-release] AID - S0021-9258(20)30040-5 [pii] AID - RA119.009437 [pii] AID - 10.1074/jbc.RA119.009437 [doi] PST - ppublish SO - J Biol Chem. 2019 Dec 27;294(52):20246-20258. doi: 10.1074/jbc.RA119.009437. Epub 2019 Oct 16.