dc.contributor.author
Freund, Christian
dc.contributor.author
Höfer, Thomas
dc.date.accessioned
2019-12-05T08:52:23Z
dc.date.available
2019-12-05T08:52:23Z
dc.identifier.uri
https://refubium.fu-berlin.de/handle/fub188/26046
dc.identifier.uri
http://dx.doi.org/10.17169/refubium-25805
dc.description.abstract
Introduction:
Antigen processing and loading of peptides onto MHC class II molecules is a multistep process that involves vesicular transport of the MHCII molecules along the secretory pathway, where they eventually merge with antigen-containing endocytic vesicles or phagosomes (1). It is within these late endosomal or lysosomal compartments that protein antigens become degraded by proteases, most prominently by cathepsins, and where catalyzed peptide exchange by HLA-DM fulfills its role in the efficient replacement of the invariant chain-derived peptide CLIP by high-affinity pathogen- or host cell-derived peptides. Protease action may be limited by protein antigen abundance and redox conditions, while HLA-DM is regulated at several stages, including by expression levels, pH, or the co-expression of the competitive inhibitor HLA-DO. HLA-DM activity leads to significant changes in the immunopeptidome of antigen-presenting cells, thereby tailoring T cell responses and often shifting antigenicity toward high-affinity immunodominant epitopes (2). Control of DM activity by DO has been described to be of prime importance in thymic epithelial cells, in a subset of dendritic cells, and in B cells when entering the germinal centers for affinity maturation and class switching (3, 4). In all of these cases, the switch from a broader, self-peptide (CLIP) dominated immunopeptidome to a more focused repertoire is necessitated by the requirement for more stringent antigen presentation, often preceding more intense T cell reactivity and proliferation. Here, we review data on this cellular switch in the functionality of antigen presentation and propose that it is promoted by an as yet poorly understood molecular switch. Acknowledging that general biophysical parameters such as pH and redox are important for antigen processing in general, an elusive DM-DO switch is postulated that would allow rapid and strong shifts in immunopeptidomes. We capitalize on theoretical considerations to back our opinion that a regulatable switch would have the advantage of allowing for a rapid and possibly signal-dependent change in the peptide selection process, as might be required in the context of rapidly changing immunological conditions.
en
dc.rights.uri
https://creativecommons.org/licenses/by/4.0/
dc.subject
MHC class II
en
dc.subject
exchange catalyst
en
dc.subject.ddc
500 Naturwissenschaften und Mathematik::570 Biowissenschaften; Biologie::572 Biochemie
dc.title
A Missing Switch in Peptide Exchange for MHC Class II Molecules
dc.type
Wissenschaftlicher Artikel
dcterms.bibliographicCitation.articlenumber
2513
dcterms.bibliographicCitation.doi
10.3389/fimmu.2019.02513
dcterms.bibliographicCitation.journaltitle
Frontiers in Immunology
dcterms.bibliographicCitation.volume
10
dcterms.bibliographicCitation.url
https://doi.org/10.3389/fimmu.2019.02513
refubium.affiliation
Biologie, Chemie, Pharmazie
refubium.affiliation.other
Institut für Chemie und Biochemie
refubium.note.author
Die Publikation wurde aus Open Access Publikationsgeldern der Freien Universität Berlin und der DFG gefördert.
refubium.resourceType.isindependentpub
no
dcterms.accessRights.openaire
open access