On the role of high- and low-abundance class II MHC-peptide complexes in the thymic positive selection of CD4+ T cells

Bartosz Chmielowski, Pawel Muranski, Pawel Kisielow, Leszek Ignatowicz

Research output: Contribution to journalArticle

12 Scopus citations


The role of self-peptides bound to MHC molecules in the selection of T cells in the thymus remains controversial. Here, we have tested whether a high-abundance single class II MHC-peptide complex has a dominant effect on the repertoire of CD4+ T cells selected by low-abundance class II MHC-peptide complexes. For these studies, we have used H-2b mice that lack an invariant chain (li) (Abli-) and their transgenic variant (AbAbEpli-) that co-expresses Ab molecules covalently bound with a single peptide Ep(52-68). In these latter mice, close to 50% of all Ab molecules are occupied by Ep(52-68) peptide. Although the AbEp complex was abundantly expressed in the thymus under conditions excluding negative selection on bone marrow-derived cells, no striking quantitative difference between repertoires of TCR expressed on CD4+ T cells in Abli- and AbAbEpli- mice was noticed. Our results are consistent with the view that diverse, low-abundance self-peptides play an important role in thymic positive selection and do not support the notion that dominant, high-abundance peptides may be critical for shaping the TCR repertoire.

Original languageEnglish (US)
Pages (from-to)67-72
Number of pages6
JournalInternational Immunology
Issue number1
Publication statusPublished - Jan 1 2000



  • MHC-peptide complex
  • Positive selection
  • T cell repertoire

ASJC Scopus subject areas

  • Immunology

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