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.
Studies on circulating T cells and antibodies in newly diagnosed type 1 diabetic patients and rodent models of autoimmune diabetes suggest that beta-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 beta-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.
Neophytou
P I
PI
Department of Clinical Biochemistry, University of Cambridge, Addenbrooke's Hospital, United Kingdom.
Roep
B O
BO
Arden
S D
SD
Muir
E M
EM
Duinkerken
G
G
Kallan
A
A
de Vries
R R
RR
Hutton
J C
JC
D000595:Amino Acid Sequence; D001324:Autoantigens / Q000235:genetics*; D001483:Base Sequence; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D003001:Cloning, Molecular / Q000379:methods; D018076:DNA, Complementary / Q000235:genetics; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology*; D018604:Epitope Mapping / Q000379:methods*; D015723:Gene Library; D006801:Humans; D007515:Islets of Langerhans / Q000276:immunology*; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data
D001324:Autoantigens; D018076:DNA, Complementary