title: Positional scanning-synthetic peptide library-based analysis of self- and pathogen-derived peptide cross-reactivity with tumor-reactive Melan-A-specific CTL.
abstract: Synthetic combinatorial peptide libraries in positional scanning format (PS-SCL) have recently emerged as a useful tool for the analysis of T cell recognition. This includes identification of potentially cross-reactive sequences of self or pathogen origin that could be relevant for the understanding of TCR repertoire selection and maintenance, as well as of the cross-reactive potential of Ag-specific immune responses. In this study, we have analyzed the recognition of sequences retrieved by using a biometric analysis of the data generated by screening a PS-SCL with a tumor-reactive CTL clone specific for an immunodominant peptide from the melanocyte differentiation and tumor-associated Ag Melan-A. We found that 39% of the retrieved peptides were recognized by the CTL clone used for PS-SCL screening. The proportion of peptides recognized was higher among those with both high predicted affinity for the HLA-A2 molecule and high predicted stimulatory score. Interestingly, up to 94% of the retrieved peptides were cross-recognized by other Melan-A-specific CTL. Cross-recognition was at least partially focused, as some peptides were cross-recognized by the majority of CTL. Importantly, stimulation of PBMC from melanoma patients with the most frequently recognized peptides elicited the expansion of heterogeneous CD8(+) T cell populations, one fraction of which cross-recognized Melan-A. Together, these results underline the high predictive value of PS-SCL for the identification of sequences cross-recognized by Ag-specific T cells.
authors.affiliation: Division of Clinical Onco-Immunology, Ludwig Institute for Cancer Research, Lausanne Branch, University Hospital, Lausanne, Switzerland.
authors.forename: Verena
authors.initials: V
authors.lastname: Rubio-Godoy
authors.forename: Valérie
authors.initials: V
authors.lastname: Dutoit
authors.forename: Yingdong
authors.initials: Y
authors.lastname: Zhao
authors.forename: Richard
authors.initials: R
authors.lastname: Simon
authors.forename: Philippe
authors.initials: P
authors.lastname: Guillaume
authors.forename: Richard
authors.initials: R
authors.lastname: Houghten
authors.forename: Pedro
authors.initials: P
authors.lastname: Romero
authors.forename: Jean-Charles
authors.initials: JC
authors.lastname: Cerottini
authors.forename: Clemencia
authors.initials: C
authors.lastname: Pinilla
authors.forename: Danila
authors.initials: D
authors.lastname: Valmori
mesh_terms: D000942:Antigens, Bacterial / Q000276:immunology* / Q000378:metabolism; D000951:Antigens, Neoplasm / Q000276:immunology / Q000378:metabolism; D000956:Antigens, Viral / Q000276:immunology* / Q000378:metabolism; D001324:Autoantigens / Q000276:immunology* / Q000378:metabolism; D002999:Clone Cells; D020650:Combinatorial Chemistry Techniques / Q000379:methods*; D003601:Cytotoxicity Tests, Immunologic / Q000379:methods; D003602:Cytotoxicity, Immunologic; D018984:Epitopes, T-Lymphocyte / Q000276:immunology / Q000378:metabolism; D015789:HLA-A2 Antigen / Q000378:metabolism; D006801:Humans; D058965:MART-1 Antigen; D008545:Melanoma / Q000276:immunology; D009363:Neoplasm Proteins / Q000276:immunology* / Q000378:metabolism; D010446:Peptide Fragments / Q000032:analysis / Q000138:chemical synthesis / Q000276:immunology; D019151:Peptide Library; D011485:Protein Binding / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D000942:Antigens, Bacterial; D000951:Antigens, Neoplasm; D000956:Antigens, Viral; D001324:Autoantigens; D018984:Epitopes, T-Lymphocyte; D015789:HLA-A2 Antigen; D058965:MART-1 Antigen; C548667:MLANA protein, human; D009363:Neoplasm Proteins; D010446:Peptide Fragments; D019151:Peptide Library