Recognition of a subregion of human proinsulin by class I-restricted T cells in type 1 diabetic patients

doi:10.1073/pnas.0504230102

Recognition of a subregion of human proinsulin by class I-restricted T cells in type 1 diabetic patients

^*Institut National de la Santé et de la Recherche Médicale U561, Hôpital Cochin-Saint Vincent de Paul, Université Paris V, 75014 Paris, France; ^†Centre National de la Recherche Scientifique Unité Propre de Recherche 9021, Institut de Biologie Moléculaire et Cellulaire, 67000 Strasbourg, France; ^‡Institut National de la Santé et de la Recherche Médicale U567, Centre National de la Recherche Scientifique Unité Mixte de Recherche 8104, Institut Cochin, Université Paris V, 75014 Paris, France; and ^§Service d'Immunologie Clinique, Hôpital Cochin-Saint Vincent de Paul, 75014 Paris, France

Communicated by Hugh O. McDevitt, Stanford University School of Medicine, Stanford, CA, May 24, 2005 (received for review March 15, 2005)

Abstract

Proinsulin is a key autoantigen in type 1 diabetes. Evidence in the mouse has underscored the importance of the insulin B chain region in autoimmunity to pancreatic beta cells. In man, a majority of proteasome cleavage sites are predicted by proteasome cleavage algorithms within this region. To study CD8⁺ T cell responses to the insulin B chain and adjacent C peptide, we selected 8- to 11-mer peptides according to proteasome cleavage patterns obtained by digestion of two peptides covering proinsulin residues 28 to 64. We studied their binding to purified HLA class I molecules and their recognition by T cells from diabetic patients. Peripheral blood mononuclear cells from 17 of 19 recent-onset and 12 of 13 long-standing type 1 diabetic patients produced IFN-γ in response to proinsulin peptides as shown by using an ELISPOT assay. In most patients, the response was against several class I-restricted peptides. Nine peptides were recognized within the proinsulin region covering residues 34 to 61. Four yielded a high frequency of recognition in HLA-A1 and -B8 patients. Three peptides located in the proinsulin region 41–51 were shown to bind several HLA molecules and to be recognized in a high percentage of diabetic patients.

Footnotes

↵ ¶ To whom correspondence should be addressed. E-mail: boitard{at}paris5.inserm.fr.
Abbreviations: PBMCs, peripheral blood mononuclear cells; NOD, nonobese diabetic.