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Bilderbeek RJC, Baranov MV, van den Bogaart G, Bianchi F. Transmembrane Helices Are an Over-Presented and Evolutionarily Conserved Source of Major Histocompatibility Complex Class I and II Epitopes. Front Immunol 2022; 12:763044. [PMID: 35087515 PMCID: PMC8787072 DOI: 10.3389/fimmu.2021.763044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 12/02/2021] [Indexed: 11/28/2022] Open
Abstract
Cytolytic T cell responses are predicted to be biased towards membrane proteins. The peptide-binding grooves of most alleles of histocompatibility complex class I (MHC-I) are relatively hydrophobic, therefore peptide fragments derived from human transmembrane helices (TMHs) are predicted to be presented more often as would be expected based on their abundance in the proteome. However, the physiological reason of why membrane proteins might be over-presented is unclear. In this study, we show that the predicted over-presentation of TMH-derived peptides is general, as it is predicted for bacteria and viruses and for both MHC-I and MHC-II, and confirmed by re-analysis of epitope databases. Moreover, we show that TMHs are evolutionarily more conserved, because single nucleotide polymorphisms (SNPs) are present relatively less frequently in TMH-coding chromosomal regions compared to regions coding for extracellular and cytoplasmic protein regions. Thus, our findings suggest that both cytolytic and helper T cells are more tuned to respond to membrane proteins, because these are evolutionary more conserved. We speculate that TMHs are less prone to mutations that enable pathogens to evade T cell responses.
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Affiliation(s)
- Richèl J C Bilderbeek
- Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology (GBB) Institute, University of Groningen, Groningen, Netherlands
| | - Maksim V Baranov
- Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology (GBB) Institute, University of Groningen, Groningen, Netherlands
| | - Geert van den Bogaart
- Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology (GBB) Institute, University of Groningen, Groningen, Netherlands
| | - Frans Bianchi
- Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology (GBB) Institute, University of Groningen, Groningen, Netherlands
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Zhao SY, Li N, Luo WY, Zhang NN, Zhou RY, Li CY, Wang J. Chemical synthesis and antigenic activity of a phosphatidylinositol mannoside epitope from Mycobacterium tuberculosis. Chem Commun (Camb) 2020; 56:14067-14070. [PMID: 33104149 DOI: 10.1039/d0cc05573e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Phosphatidylinositol mannosides (PIMs) have been investigated as lipidic antigens for a new subunit tuberculosis vaccine. A non-natural diacylated phosphatidylinositol mannoside (Ac2PIM2) was designed and synthesized by mimicking the natural PIM6 processing procedure in dentritic cells. This synthetic Ac2PIM2 was achieved from α-methyl d-glucopyranoside 1 in 17 steps in 2.5% overall yield. A key feature of the strategy was extending the use of the chiral myo-inositol building block A to the O-2 and O-6 positions of the inositol unit to allow for introducing the mannose building blocks B1 and B2, and to the O-1 position for the phosphoglycerol building block C. Building block A, being a flexible core unit, may facilitate future access to other higher-order PIM analogues. A preliminary antigenic study showed that the synthetic PIM epitope (Ac2PIM2) was significantly more active than natural Ac2PIM2, which indicated that the synthetic Ac2PIM2 can be strongly immunoactive and may be developed as a potential vaccine.
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Affiliation(s)
- Shi-Yuan Zhao
- School of Pharmacy, Yancheng Teachers University, Hope Avenue South Road No. 2, Yancheng, 224007, Jiangsu Province, P. R. China.
| | - Na Li
- School of Pharmacy, Yancheng Teachers University, Hope Avenue South Road No. 2, Yancheng, 224007, Jiangsu Province, P. R. China.
| | - Wan-Yue Luo
- School of Pharmacy, Yancheng Teachers University, Hope Avenue South Road No. 2, Yancheng, 224007, Jiangsu Province, P. R. China.
| | - Nan-Nan Zhang
- School of Pharmacy, Yancheng Teachers University, Hope Avenue South Road No. 2, Yancheng, 224007, Jiangsu Province, P. R. China.
| | - Rong-Ye Zhou
- School of Pharmacy, Yancheng Teachers University, Hope Avenue South Road No. 2, Yancheng, 224007, Jiangsu Province, P. R. China.
| | - Chen-Yu Li
- School of Pharmacy, Yancheng Teachers University, Hope Avenue South Road No. 2, Yancheng, 224007, Jiangsu Province, P. R. China.
| | - Jin Wang
- School of Pharmacy, Yancheng Teachers University, Hope Avenue South Road No. 2, Yancheng, 224007, Jiangsu Province, P. R. China. and Université de Toulouse, Université Toulouse III - Paul Sabatier, 118 route de Narbonne, 31062 Toulouse Cedex 9, France and CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), 205 route de Narbonne, 31077 Toulouse, France
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