title: Precursor frequency can compensate for lower TCR expression in T cell competition during priming in vivo.
abstract: The factors controlling clonal dominance of cytotoxic T lymphocyte (CTL) responses are currently not well understood. To study the functional impact of the strength of the interaction of a T cell with an antigen-presenting cell in this context, we established a new mouse model comprised of two T cell receptor (TCR)-transgenic strains expressing the identical TCR in differing amounts, hence providing two CTL clones with different avidities but identical specificity and affinity. Utilizing this new model, we show that upon antigen challenge higher-avidity CTL expand at the expense of moderate-avidity CTL in vivo if present in equal numbers. Beyond this, moderate-avidity T cells can also contribute to a CTL response when present in excess. These results suggest that in addition to a proposed affinity/avidity threshold, the precursor frequency is important in defining clonal dominance. A new model in which TCR density and precursor frequency define the outcome of a CTL response is discussed.
authors.affiliation: Institute for Immunology, Johannes Gutenberg-University, Mainz, Germany.
authors.forename: Gerd
authors.initials: G
authors.lastname: Rechtsteiner
authors.forename: Tobias
authors.initials: T
authors.lastname: Warger
authors.forename: Matthias
authors.initials: M
authors.lastname: Hofmann
authors.forename: Hans-Georg
authors.initials: HG
authors.lastname: Rammensee
authors.forename: Hansjörg
authors.initials: H
authors.lastname: Schild
authors.forename: Markus P
authors.initials: MP
authors.lastname: Radsak
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D017951:Antigen Presentation / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D005434:Flow Cytometry; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D013234:Stem Cells / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D011948:Receptors, Antigen, T-Cell