1704225
Ontology highlight
ABSTRACT:
PROVIDER: PRJEB23308 | ENA |
REPOSITORIES: ENA
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Project description:The extreme polymorphisms of human leukocyte antigen (HLA) class I proteins result in structural variations in their peptide binding sites to achieve diversity in antigen presentation. External factors could independently constrict or alter HLA class I peptide repertoires. Such effects of the assembly factor tapasin were assessed for HLA-B*44:05 (Y116) and a close variant, HLA-B*44:02 (D116), which have low and high tapasin dependence, respectively, for their cell surface expression. Analyses of the HLA-B*44:05 peptidomes in the presence and absence of tapasin reveal that peptides with C-terminal tryptophans and higher predicted affinities are preferentially selected by tapasin, coincident with reduced frequencies of peptides with other C-terminal amino acids, including leucine. Comparisons of the HLA-B*44:05 and HLA-B*44:02 peptidomes indicate the expected structure-based alterations near the peptide C-termini, but also C-terminal amino acid frequency and predicted affinity changes among the unique and shared peptide groups for B*44:02 and B*44:05. Overall, these findings indicate that the presence of tapasin and the tapasin-dependence of assembly alter HLA class I peptide binding preferences at the peptide C-terminus. The particular C-terminal amino acid preferences that are altered by tapasin are expected to be determined by the intrinsic peptide binding specificities of HLA class I allotypes. Additionally, the findings suggest that tapasin deficiency and reduced tapasin dependence expand the permissive affinities of HLA class I bound peptides, consistent with prior findings that HLA class I allotypes with low tapasin dependence have increased breadth of CD8+ T cell epitope presentation and are more protective in HIV infections.
2024-07-15 | PXD046825 | Pride
Project description:Investigation of the repertoire of peptide ligands of highly similar Major Histocompatibility complex (MHC) class I allomorphs differing in tapasin dependence; HLA-B*44:02 (tapasin dependent), HLA-B*44:05 (tapasin independent) and HLA-B*44:05 W147A mutant (tapasin dependent).
2025-06-02 | PXD054743 | Pride
Project description:Major histocompatibility complex class I (MHC-I) molecules play a key part in the adaptive immune response through the presentation of antigens to CD8+ T cells. The high degree of polymorphism in MHC-I leads to significant variation in their dependence on components of the antigen processing and presentation pathway such as TAP and tapasin, and their affinity for the peptide editor TAPBPR. Here, we investigated the influence of TAPBPR on the cell surface phenotype and peptide repertoire presented by two human leukocyte antigen (HLA) class I allotypes, HLA-B*44:02 and -B*44:05, which are known to differ drastically in their dependence on tapasin. While TAPBPR exhibits a reduced ability to bind to HLA-B molecules compared to HLA-A, we found that it could bind to both HLA-B*44:02 and -B*44:05. In contrast to tapasin depletion, loss of TAPBPR has a limited effect on cell surface expression of these two molecules. Analysis of the immunopeptidomes presented in the presence and absence of TAPBPR revealed while TAPBPR expression restricted the peptide repertoire presented on HLA-B*44:05, it diversified the repertoire presented on HLA-B*44:02. Overall, TAPBPR improved the predicted affinity of the peptides displayed on both the HLA-B*44 molecules. Furthermore, TAPBPR enhanced the presentation of peptides containing a C-terminal tryptophan residue. Our results show that TAPBPR can significantly impact the peptide repertoire of MHC-I molecules to which it binds weakly. Furthermore, this represents the first study which points to a role for TAPBPR in the selection of a specific peptide sequence on MHC class I molecules.
2025-10-24 | PXD063219 | Pride
Project description:Sorted cells from bone marrow and rectal mucosa of SIV-infected rhesus macaques were analyzed for expression of factors associated with plasma cell recruitment, adhesion, or maintenance mRNA expression anaylsis was performed on 16 CD2-CD19-CD20-HLA-DR+ and 16 CD2-CD19-CD20-HLA-DR- bone marrow cells, and 7 CD2-CD19-CD20-HLA-DR+ and 3 CD2-CD19-CD20-HLA-DR- rectal cells using a custom CodeSet produced by NanoString Technologies containing 44 niche factor genes of interst, 12 cell-type specific genes, and 9 reference genes identified in Genevestigator.
2016-12-16 | GSE81609 | GEO