The goals of this proposal are to evaluate the role of DM, a non-classical MHC class II heterodimer, in the selection of immunodominant epitopes from a given protein. Our recent data strongly suggested that DM selectively dissociates complexes of peptide-MHC that have floppy conformation and leaves compact peptide/MHC complexes unaffected. We propose that this preferred interaction with a specific conformation of MHC class II, might influence epitope selection from the pool of all other epitopes that can bind to MHC class II. A new assay is designed here to investigate the role of DM in determinant selection by a given MHC class II. Using purified empty HLA-DR1, soluble HLA-DM, and purified Influenza Hemagglutinin (HA) as a model antigen, we will generate antigenic epitopes that remain bound to DR1 in the presence of DM. We would begin with purified influenza hemagglutinin that has a known immunodominant epitope of HA306- 318 in DR1 expressing individuals. Using enzymes with known activity in antigen processing, such as cathepsins, HA protein will be subjected to enzymatic digestion and DR1 binding in the presence of DR1 and DM in Aim I. Mass spectrometric analyzes of the HPLC fractionated peptides eluted from DR1 under the above condition will reveal whether HA306-318 is selected as a predominant peptide.
Aim 2 will investigate effects of HLA-DO on regulation of DM and selection of immunodominant epitopes using similar approach to Aim I.
Aim 3 will examine interactions of purified DO with DM in vitro and Aim IV will test biological activity of identified epitopes in vivo. Once the feasibility of the method is established, it should be applicable for identification of antigenic epitopes of any complex proteins from pathogenic organisms. The antigenic epitopes might be used in class II tetramer assays for staining of specific activated T cells in vivo and in design of vaccines and as correlates of immunity for immunization efficacy. This research has great impacts on discovering immunodominant epitopes of infectious agents relevant to biodefense. ? ? ?
| Sadegh-Nasseri, Scheherazade; Kim, AeRyon (2018) Selection of immunodominant epitopes during antigen processing is hierarchical. Mol Immunol : |
| Darrah, Erika; Kim, AeRyon; Zhang, Xi et al. (2017) Proteolysis by Granzyme B Enhances Presentation of Autoantigenic Peptidylarginine Deiminase 4 Epitopes in Rheumatoid Arthritis. J Proteome Res 16:355-365 |
| Sadegh-Nasseri, Scheherazade; Kim, AeRyon (2015) Exogenous antigens bind MHC class II first, and are processed by cathepsins later. Mol Immunol 68:81-4 |
| Kim, AeRyon; Sadegh-Nasseri, Scheherazade (2015) Determinants of immunodominance for CD4 T cells. Curr Opin Immunol 34:9-15 |
| Kim, AeRyon; Hartman, Isamu Z; Poore, Brad et al. (2014) Divergent paths for the selection of immunodominant epitopes from distinct antigenic sources. Nat Commun 5:5369 |
| Poluektov, Yuri O; Kim, Aeryon; Hartman, Isamu Z et al. (2013) HLA-DO as the optimizer of epitope selection for MHC class II antigen presentation. PLoS One 8:e71228 |
| Poluektov, Yuri O; Kim, Aeryon; Sadegh-Nasseri, Scheherazade (2013) HLA-DO and Its Role in MHC Class II Antigen Presentation. Front Immunol 4:260 |
| Kim, Tae Hyung; Swierczewska, Magdalena; Oh, Yumin et al. (2013) Mix to validate: a facile, reversible PEGylation for fast screening of potential therapeutic proteins in vivo. Angew Chem Int Ed Engl 52:6880-4 |
| Kim, AeRyon; Ishizuka, Isabel; Hartman, Isamu et al. (2013) Studying MHC class II peptide loading and editing in vitro. Methods Mol Biol 960:447-459 |
| Sadegh-Nasseri, Scheherazade; Chou, Chih-Ling; Hartman, Isamu Z et al. (2012) How HLA-DM works: recognition of MHC II conformational heterogeneity. Front Biosci (Schol Ed) 4:1325-32 |
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