Dendritic cells (DCs) take up antigen in the periphery, migrate to secondary lymphoid organs, and present processed antigen fragments to adaptive immune cells and thus prime antigen-specific immunity. During local inflammation, recirculating monocytes are recruited from blood to the inflamed tissue, where they differentiate to macrophages and DCs. In this study, we found that monocytes showed high transporter associated with antigen processing (TAP)-dependent peptide compartmentalization and that after antigen pulsing, they were not able to efficiently stimulate antigen-specific T lymphocytes. Nevertheless, upon in vitro differentiation to monocyte-derived DCs, TAP-dependent peptide compartmentalization as well as surface major histocompatibility complex I turnover decreased and the cells efficiently restimulated T lymphocytes. Although TAP-dependent peptide compartmentalization decreased during DC differentiation, TAP expression levels increased. Furthermore, TAP relocated from early endosomes in monocytes to the endoplasmic reticulum (ER) and lysosomal compartments in DCs. Collectively, these data are compatible with the model that during monocyte-to-DC differentiation, the subcellular relocation of TAP and the regulation of its activity assure spatiotemporal separation of local antigen uptake and processing by monocytes and efficient T-lymphocyte stimulation by DCs.
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http://dx.doi.org/10.1182/bloodadvances.2018027268 | DOI Listing |
J Virol
December 2024
Biological Sciences, Towson University, Towson, Maryland, USA.
Unlabelled: Kaposi's sarcoma herpesvirus (KSHV) is the causative agent of Kaposi's sarcoma and is associated with primary effusion lymphoma (PEL), multicentric Castleman's disease, and two inflammatory diseases. KSHV-associated cancers are primarily associated with genes expressed during latency, while other pathologies are associated with lytic gene expression. The major lytic switch of the virus, Replication and Transcription Activator (RTA), interacts with cellular machinery to co-opt the host ubiquitin proteasome system to evade the immune response as well as activate the program of lytic replication.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
March 2024
Laboratory of Virus Molecular Biology, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk 80-307, Poland.
The transporter associated with antigen processing (TAP) is a key player in the major histocompatibility class I-restricted antigen presentation and an attractive target for immune evasion by viruses. Bovine herpesvirus 1 impairs TAP-dependent antigenic peptide transport through a two-pronged mechanism in which binding of the UL49.5 gene product to TAP both inhibits peptide transport and triggers its proteasomal degradation.
View Article and Find Full Text PDFbioRxiv
September 2023
Laboratory of Virus Molecular Biology, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, 80-307 Gdańsk, Poland.
The transporter associated with antigen processing (TAP) is a key player in the MHC class I-restricted antigen presentation and an attractive target for immune evasion by viruses. Bovine herpesvirus 1 (BoHV-1) impairs TAP-dependent antigenic peptide transport through a two-pronged mechanism in which binding of the UL49.5 gene product to TAP both inhibits peptide transport and promotes its proteasomal degradation.
View Article and Find Full Text PDFCurr Opin Immunol
August 2023
The Jill Roberts Institute for Research in Inflammatory Bowel Disease, New York, NY, USA; Joan and Sanford I. Weill Department of Medicine, New York, NY, USA; Department of Microbiology and Immunology, New York, NY, USA; Sandra and Edward Meyer Cancer Center, New York, NY, USA; Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, Weill Cornell Medicine, Cornell University, New York, NY, USA. Electronic address:
Viral blockade of the transporter associated with antigen processing (TAP) diminishes surface and endosomal recycling compartment levels of major histocompatibility complex class-I (MHC-I) in dendritic cells (DCs), and compromises both classical MHC-I presentation and canonical cross-presentation during infection to impair CD8 T-cell immunity. Virus-specific CD8 T cells are thought to be cross-primed mostly by uninfected TAP-sufficient DCs through cross-presentation of viral peptides from internalized virus-infected dying cells. The dilemma is that CD8 T cells primed to TAP-dependent viral peptides are mismatched to the TAP-independent epitopes presented on tissues infected with immune-evasive viruses.
View Article and Find Full Text PDFMol Immunol
February 2023
Institute für Biochemie Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Biochemistry, Berlin, Germany. Electronic address:
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