Language：English   Publisher：Oxford University Press  

HLA-DP5陽性スギ花粉症患者から、スギ花粉抗原Cry j 1由来N末端側隣接領域(NF)4残基を含む13残基のペプチド(NF-pCj1)特異的でHLA-DP5限定CD4+T細胞クローンを作成した。NF-pCj1発現mDC1細胞によるマウスTG40細胞の活性化でのIL-2産生を解析した。Ser(-2)とLys(-3)がGluになった二重変異によりT細胞の活性化は低下したが、T細胞受容体へのNF-pCj1・HLA-DP5の親和性には影響がなかった。

Language：English   Publisher：International Immunology  

Cry j 1 is a major allergen present in Japanese cedar (Cryptomeria japonica) pollens. Peptides with the core sequence of KVTVAFNQF from Cry j 1 ('pCj1') bind to HLA-DP5 and activate Th2 cells. In this study, we noticed that Ser and Lys at positions -2 and -3, respectively, in the N-terminal flanking (NF) region to pCj1 are conserved well in HLA-DP5-binding allergen peptides. A competitive binding assay showed that the double mutation of Ser(-2) and Lys(-3) to Glu [S(P-2)E/K(P-3)E] in a 13-residue Cry j 1 peptide (NF-pCj1) decreased its affinity for HLA-DP5 by about 2-fold. Similarly, this double mutation reduced, by about 2-fold, the amount of NF-pCj1 presented on the surface of mouse antigen-presenting dendritic cell line 1 (mDC1) cells stably expressing HLA-DP5. We established NF-pCj1-specific and HLA-DP5-restricted CD4+ T-cell clones from HLA-DP5 positive cedar pollinosis (CP) patients, and analyzed their IL-2 production due to the activation of mouse TG40 cells expressing the cloned T-cell receptor by the NF-pCj1-presenting mDC1 cells. The T-cell activation was actually decreased by the S(P-2)E/K(P-3)E mutation, corresponding to the reduction in the peptide presentation by this mutation. In contrast, the affinity of NF-pCj1·HLA-DP5 for the T-cell receptor was not affected by the S(P-2)E/K(P-3)E mutation, as analyzed by surface plasmon resonance. Considering the positional and side-chain differences of these NF residues from previously reported T-cell activating sequences, the mechanisms of enhanced T-cell activation by Ser(-2) and Lys(-3) of NF-pCj1 may be novel.

DOI： 10.1093/intimm/dxad024

Web of Science

Scopus

PubMed

Publisher：Journal of Immunology  

The immunogenicity of a T cell Ag is correlated with the ability of its antigenic epitope to bind HLA and be stably presented to T cells. This presents a challenge for the development of effective cancer immunotherapies, as many self-derived tumor-associated epitopes elicit weak T cell responses, in part due to weak binding affinity to HLA. Traditional methods to increase peptide-HLA binding affinity involve modifying the peptide to reflect HLA allele binding preferences. Using a different approach, we sought to analyze whether the immunogenicity of wild-type peptides could be altered through modification of the HLA binding pocket. After analyzing HLA class I peptide binding pocket alignments, we identified an alanine 81 to leucine (A81L) modification within the F binding pocket of HLA-A*24:02 that was found to heighten the ability of artificial APCs to retain and present HLA-A*24:02-restricted peptides, resulting in increased T cell responses while retaining Ag specificity. This modification led to increased peptide exchange efficiencies for enhanced detection of low-avidity T cells and, when expressed on artificial APCs, resulted in greater expansion of Ag-specific T cells from melanoma-derived tumor-infiltrating lymphocytes. Our study provides an example of how modifications to the HLA binding pocket can enhance wild-type cognate peptide presentation to heighten T cell activation.

DOI： 10.4049/jimmunol.2200305

Scopus

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2169/internalmedicine.8778-16

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1038/gene.2014.61

Event date： 2018.4

Language：Japanese  

Country：Japan  

Event date： 2017.12

Language：Japanese  

Country：Japan  

Event date： 2017.3

Language：Japanese  

Country：Japan  

Language：Japanese  

Country：Japan  

Language：Japanese  

Country：Japan