Identification of naturally processed HLA-A2--restricted proinsulin epitopes by reverse immunology.
Type 1 diabetes is thought to result from the destruction of beta-cells by autoantigen-specific T-cells. Observations in the NOD mouse model suggest that CD8+ cytotoxic T-cells play an essential role in both the initial triggering of insulitis and its destructive phase. However, little is known about the epitopes derived from human beta-cell autoantigens and presented by HLA class I molecules. We used a novel reverse immunology approach to identify HLA-A2-restricted, naturally processed epitopes derived from proinsulin, an autoantigen likely to play an important role in the pathogenesis of type 1 diabetes. Recombinant human proinsulin was digested with purified proteasome complexes to establish an inventory of potential COOH-terminals of HLA class I-presented epitopes. Cleavage data were then combined with epitope predictions based on the SYFPEITHI and BIMAS algorithms to select 10 candidate epitopes; 7 of these, including 3 with a sequence identical to murine proinsulin, were immunogenic in HLA-A2 transgenic mice. Moreover, six of six tested peptides were processed and presented by proinsulin-expressing cells. These results demonstrate the power of reverse immunology approaches. Moreover, the novel epitopes may be of significant interest in monitoring autoreactive T-cells in type 1 diabetes.
Hassainya
Yousra
Y
Institut National de la Santé et de la Recherche Médicale Unité 580, Université René Descartes, Paris, France.
Garcia-Pons
Francisco
F
Kratzer
Roland
R
Lindo
Vivian
V
Greer
Fiona
F
Lemonnier
François A
FA
Niedermann
Gabriele
G
van Endert
Peter M
PM
D018528:ATP-Binding Cassette Transporters; D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics / Q000276:immunology*; D000939:Epitopes / Q000032:analysis* / Q000737:chemistry; D005822:Genetic Vectors; D015789:HLA-A2 Antigen / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000276:immunology; D006801:Humans; D007328:Insulin; D008214:Lymphocytes / Q000276:immunology; D051379:Mice; D018448:Models, Immunological; D008969:Molecular Sequence Data; D011384:Proinsulin / Q000235:genetics / Q000276:immunology*; D011498:Protein Precursors / Q000235:genetics* / Q000276:immunology; D017386:Sequence Homology, Amino Acid; D014616:Vaccinia virus / Q000235:genetics
D018528:ATP-Binding Cassette Transporters; D000939:Epitopes; D015789:HLA-A2 Antigen; D015395:Histocompatibility Antigens Class I; D007328:Insulin; D011498:Protein Precursors; C477327:transporter associated with antigen processing (TAP); C013737:preproinsulin; D011384:Proinsulin