Positive selection of self-MHC-reactive T cells by individual peptide-MHC class II complexes Academic Article uri icon


MeSH Major

  • Antigen Presentation
  • Autoantigens
  • CD4-Positive T-Lymphocytes
  • Cell Adhesion Molecules
  • Histocompatibility Antigens Class II
  • Lectins


  • If T cells require specific interactions with MHC-bound peptides during positive selection, then the specificities of T cells selected by one peptide should be distinct from those selected by another. We have examined positive selection of CD4 T cells in four strains of mice, each overexpressing a different peptide-1-A(b)(A(b)) complex. We show that a subset of CD4 T cells is selected by the overexpressed peptide and that the specificities of the CD4 T cells, as measured by reactivity to wild-type antigen-presenting cells, vary greatly depending on which peptide is overexpressed. These differences in specificity are mediated through positive selection not negative selection. Each of the four peptide-A(b) complexes appears to adopt a different conformation, and these differences correlate with the differences in reactivity. Our results suggest that individual peptide-MHC complexes positively select different subsets of self-MHC-reactive T cells and that the conformation of the peptide-MHC complex may contribute to this process.

publication date

  • May 14, 2002



  • Academic Article



  • eng

PubMed Central ID

  • PMC124507

Digital Object Identifier (DOI)

  • 10.1073/pnas.102645699

PubMed ID

  • 12011451

Additional Document Info

start page

  • 6937

end page

  • 42


  • 99


  • 10