HLA class I epitope discovery in type 1 diabetes.
Type 1 diabetes mellitus (T1DM) results from the destruction of beta cells by autoantigen-specific T cells. In the non-obese diabetic (NOD) mouse model, CD8+ T cells play an essential role in both the initial triggering of insulitis and its destructive phase, and proinsulin (PI) is one of the dominant target antigens (Ags). However, little is known about the beta cell epitopes presented by HLA class I molecules and recognized by human CD8+ T cells. We and other groups recently applied reverse immunology approaches to identify HLA class I-restricted PI epitopes. To establish an inventory of potential naturally processed epitopes, whole human PI or the transitional region between the B-chain and C-peptide were digested with purified proteasome complexes. By combining proteasome digestion data with epitope prediction algorithms, candidate epitopes restricted by HLA-A2.1 and other HLA class I molecules were identified. We validated immunogenicity and natural processing of the identified PI epitopes in HLA-A2.1-transgenic mice, while others demonstrated recognition of multiple PI epitopes by CD8+ T cells from T1DM and healthy subjects in the context of different HLA class I molecules. These results demonstrate the power of reverse immunology strategies for epitope discovery. DNA vaccination of HLA-transgenic mice may be another rapid and efficient reverse immunology approach to map additional epitopes derived from other T1DM Ags, such as IA-2 and glutamic acid decarboxylase 65 (GAD 65). Transfer of this information to Elispot- and MHC tetramer-based assay formats should allow to reliably detect and characterize autoreactive CD8+ T cell responses in T1DM, and may open new avenues for early T1DM diagnosis and immune intervention.
van Endert
Peter
P
INSERM U580, Hôpital Necker, 161 rue de Sèvres, 75015 Paris, France. vanendert@necker.fr
Hassainya
Yousra
Y
Lindo
Vivian
V
Bach
Jean-Marie
JM
Blancou
Philippe
P
Lemonnier
François
F
Mallone
Roberto
R
D000483:Alleles; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002460:Cell Line; D003601:Cytotoxicity Tests, Immunologic; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D000939:Epitopes / Q000032:analysis* / Q000737:chemistry; D015395:Histocompatibility Antigens Class I / Q000235:genetics* / Q000276:immunology*; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D011384:Proinsulin / Q000235:genetics / Q000276:immunology*; D046988:Proteasome Endopeptidase Complex / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000276:immunology; D014616:Vaccinia virus / Q000235:genetics
D000911:Antibodies, Monoclonal; D000939:Epitopes; D015395:Histocompatibility Antigens Class I; D019444:Vaccines, DNA; D011384:Proinsulin; D046988:Proteasome Endopeptidase Complex