T-cell epitope analysis using subtracted expression libraries (TEASEL): application to a 38-kDA autoantigen recognized by T cells from an insulin-dependent diabetic patient.

Abstract

Studies on circulating T cells and antibodies in newly diagnosed type 1 diabetic patients and rodent models of autoimmune diabetes suggest that ,B-cell membrane proteins of 38 kDa may be important molecular targets of autoimmune attack Biochemical approaches to the isolation and identification of the 38-kDa autoantigen have been hampered by the restricted availability of islet tissue and the low abundance of the protein. A procedure of epitope analysis for CD4+ T cells using subtracted expression libraries (TEASEL) was developed and used to clone a 70-amino acid pancreatic (8-cell peptide incorporating an epitope recognized by a 38-kDa-reactive CD4+ T-cell clone (1C6) isolated from a human diabetic patient. The minimal epitope was mapped to a 10-amino acid synthetic peptide containing a DR1 consensus binding motif. Data base searches did not reveal the identity of the protein, though a weak homology to the bacterial superantigens SEA (Streptococcus pyogenes exotoxin A) and SEB (Staphylococcus aureus enterotoxin B) (23% identity) was evident. The TEASEL procedure might be used to identify epitopes of other autoantigens recognized by CD4+ T cells in diabetes as well as be more generally applicable to the study low-abundance autoantigens in other tissue-specific autoimmune diseases.

Homing of human autoreactive T cells into pancreatic tissue of NOD-scid mice

“…Additionally, these T cells express HLA-A1/A26 and HLA-B8/B57. The second islet-specific autoreactive T cell clone (1C6) recognises insulin secretory granules or 38-kDa antigen [9] and a peptide epitope p(51-70) in the context of HLA-DR1 [17]. Additionally, these T cells express HLA-A2/A3 and HLA-B39/B44.…”

The role of T-cells in the pathogenesis of Type 1 diabetes: From cause to cure

“…Firstly, autoreactive T-cell clones have been used to identify candidate islet autoantigens that had not previously been characterised by autoantibodies [53,54]. Secondly, autoreactive T-cell clones isolated from newly diagnosed or pre-diabetic patients have been used to design and study potential immunotherapeutic strategies in vitro, such as chimeric soluble ICAM-1 and -3 (important intercellular adhesion molecules required for costimulation of T-cells and extravasation) [55,56], proteases [57], and altered peptide ligands of autoantigenic peptide epitopes [58].…”

Antigen Targets of Type 1 Diabetes Autoimmunity

“…A third approach to identify b-cell autoantigens involved a cell biological strategy based on selective expression of b-cell proteins as defined by complementary DNA (cDNA) subtraction libraries or microarrays (Miyazaki et al 1994;Arden et al 1996;Neophytou et al 1996). In retrospect, proteins that were initially identified through their stimulation of autoimmune responses (imogen-38, IGRP, IA-2, and IA-2ß) were confirmed by these experiments, whereas new candidates were identified that subsequently proved to be relevant and potentially associated with the immunopathogenesis of type 1 diabetes, such as ICA69 and most recently the zinc transporter 8 (ZnT8) (Wenzlau et al 2010).…”