Vesicles bearing MHC class II molecules mediate transfer of antigen from antigen-presenting cells to CD4+ T cells

Eur J Immunol. 1999 Apr;29(4):1363-73. doi: 10.1002/(SICI)1521-4141(199904)29:04<1363::AID-IMMU1363>3.0.CO;2-0.


Previous studies have provided evidence that myelin basic protein (MBP)-specific rat T cells acquire antigen via transfer of preformed peptide/MHC class II complexes from splenic antigen-presenting cells (APC). The purpose of the present study was to determine how T cells acquire peptide/MHC class II complexes from APC in vitro. Our results show that a MHC class II+ T cell line, R1-trans, released MHC class II-bearing vesicles that directly stimulated MBP-specific CD4+ T cells. Vesicles expressing complexes of MHC class II and MBP were also specifically cytotoxic to MBP-specific T cells. Surviving T cells acquired MHC class II/antigen complexes from these vesicles by a mechanism that did not require protein synthesis but depended on specific TCR interactions with peptide/self MHC complexes. Furthermore, MBP/MHC class II-bearing vesicles enabled T cells to present MBP to other T cell responders. These studies provide evidence that APC release vesicles expressing preformed peptide/MHC class II complexes that interact with clonotypic TCR, allowing MHC class II acquisition by T cells. Vesicular transport of antigen/MHC class II complexes from professional APC to T cells may represent an important mechanism of communication among cells of the immune system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigen Presentation*
  • Antigen-Presenting Cells / metabolism*
  • Brefeldin A / pharmacology
  • CD4-Positive T-Lymphocytes / metabolism*
  • Cell Line
  • Cycloheximide / pharmacology
  • Histocompatibility Antigens Class II / metabolism*
  • Rats
  • Rats, Inbred BN
  • Rats, Inbred Lew


  • Histocompatibility Antigens Class II
  • Brefeldin A
  • Cycloheximide