Peptide presentation by the MHC class Ib molecule, H2-M3

Geoffrey P. Smith, Vikram M. Dabhi, Eric G. Pamer, Kirsten Fischer Lindahl

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


The presentation of N-formylated peptides to cytotoxic T cells is restricted to the mouse class I MHC molecule, H2-M3. Previous studies have shown that M3 is unable to present unformylated peptldes. We demonstrate that the unformylated ND1 peptide can sensitize M3wt-transfected fibroblasts for killing by ND1-specific cytotoxlc T cells. At 1 /M, both N-formylated and unformylated ND1 peptides induced equivalent levels of killing. However, the concentrations required for half maximal killing differed by 104-fold, from 10-50 pM for N-formylated ND1 to 100 nM for unformylated ND1. The peptide binding groove of M3 differs from other class I molecules at three highly conserved positions: 34 (V→Q), 167 (W→L) and 171 (Y→F). Site-directed mutagenesis was used to determine the importance of these changes In the presentation of N-formylated peptldes by M3. Cell lines expressing the mutations Q34V, L167W or F171Y all presented the N-formylated ND1 peptide equally well to ND1-specific T cells. The N-formylated ND1 peptide was also presented by a triple mutant, containing substitutions at all three positions. Q34, L167 and F171 are therefore not required individually, nor in combination, for the presentation of N-formylated peptides by M3. However, all three point mutations did affect killing by alloreactive, M3-specific T cells. F171Y was the least damaging mutation, affecting only one of the two T cell lines tested. By contrast, both T cell lines failed to kill Q34V and L167W targets. Q34 and L167 are thus important determinants In the M3-speciflc CTL response.

Original languageEnglish (US)
Pages (from-to)1917-1926
Number of pages10
JournalInternational Immunology
Issue number12
StatePublished - Dec 1994


  • AAformyl methionine
  • Listeria monocytogenes
  • Maternally transmitted antigen
  • Non-classical MHC
  • Site-directed mutagenesis
  • T cell recognition

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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