The identification of CD4+ T cell epitopes with dedicated synthetic peptide libraries.
For a large number of T cell-mediated immunopathologies, the disease-related antigens are not yet identified. Identification of T cell epitopes is of crucial importance for the development of immune-intervention strategies. We show that CD4+ T cell epitopes can be defined by using a new system for synthesis and screening of synthetic peptide libraries. These libraries are designed to bind to the HLA class II restriction molecule of the CD4+ T cell clone of interest. The screening is based on three selection rounds using partial release of 14-mer peptides from synthesis beads and subsequent sequencing of the remaining peptide attached to the bead. With this approach, two peptides were identified that stimulate the beta cell-reactive CD4+ T cell clone 1c10, which was isolated from a newly diagnosed insulin-dependent diabetes mellitus patient. After performing amino acid-substitution studies and protein database searches, a Haemophilus influenzae TonB-derived peptide was identified that stimulates clone 1c10. The relevance of this finding for the pathogenesis of insulin-dependent diabetes mellitus is currently under investigation. We conclude that this system is capable of determining epitopes for (autoreactive) CD4+ T cell clones with previously unknown peptide specificity. This offers the possibility to define (auto)antigens by searching protein databases and/or to induce tolerance by using the peptide sequences identified. In addition the peptides might be used as leads to develop T cell receptor antagonists or anergy-inducing compounds.
Hiemstra
H S
HS
Department of Immunohematology and Blood Bank, Leiden University Hospital, University of Leiden, 2300 RC Leiden, The Netherlands.
Duinkerken
G
G
Benckhuijsen
W E
WE
Amons
R
R
de Vries
R R
RR
Roep
B O
BO
Drijfhout
J W
JW
D000595:Amino Acid Sequence; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002999:Clone Cells; D016208:Databases, Factual; D000939:Epitopes / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry; D019151:Peptide Library
D000939:Epitopes; D009842:Oligopeptides; D019151:Peptide Library