Naturally processed heterodimeric disulfide-linked insulin peptides bind to major histocompatibility class II molecules on thymic epithelial cells

Research output: Contribution to journalArticle


We determined whether disulfide-linked insulin peptides that are immunogenic in vitro for CD4+ T cells bind to major histocompatibility complex class II in vivo. Radiolabeled recombinant human insulin (rHI) was injected into BALB/c mice, and processed rHI peptides bound to I-A(d) molecules on different thymic antigen-presenting cells were characterized. The A6-A11/B7-B19 and A19-A21/B14-B21 disulfide-linked I-A(d)-bound rHI peptides were isolated from thymic epithelial cells but not dendritic cells. While both thymic epithelial cells and dendritic cells present rHI to HI/I- A(d)-specific T cells, these antigen-presenting cells do not present the reduced or nonreduced forms of the disulfide-linked rHI peptides. Thus, a naturally processed disulfide-linked peptide can bind to major histocompatibility complex class II in vivo. The potential role of these peptides in immunological tolerance is discussed.


  • Frederique Forquet
  • Mirko Hadzija
  • John W. Semple
  • Edwin Speck
  • Terry L. Delovitch
External organisations
  • University of Toronto
Research areas and keywords


  • thymic antigen-presenting cells
Original languageEnglish
Pages (from-to)3936-3940
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number9
Publication statusPublished - 1994 Apr 26
Publication categoryResearch
Externally publishedYes