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Selection of antigen-specific T cells by a single IEk peptide combination.

Liu CP, Parker D, Kappler J, Marrack P - J. Exp. Med. (1997)

Bottom Line: Some of the TCRs on the selected T cells were related to those on cells from normal mice and some were not.IEk bound to the Hb variant, on the other hand, did not select any T cells which could react with IEk + MCC.These results demonstrate that although positive selection is a partially degenerate event, the sequence of the peptide involved in positive selection controls the selected repertoire.

View Article: PubMed Central - PubMed

Affiliation: Howard Hughes Medical Institute, National Jewish Medical and Research Center, Denver, Colorado 80206, USA.

ABSTRACT
In normal mice, major histocompatibility complex (MHC) proteins are bound to many different peptides, derived from the proteins of their host. In the thymus, the diversity of this collection of MHC + peptide ligands allows thymocytes bearing many different T cell receptors (TCRs) to mature by low avidity reactions between the MHC + peptide ligands and the thymocyte TCRs. To investigate this problem, the selection of T cells specific for a well-studied combination of MHC + peptide, IEk + moth cytochrome c 88-103 (MCC), was investigated. Mice were created that expressed IEk bound to a single peptide, either a variant of MCC in which a critical TCR contact residue, 99K, was changed to A, or a variant of a mouse hemoglobin 64-76 (Hb) peptide, 72A. IEk bound to the MCC variant caused the clonal deletion of some T cells specific for the IEk + MCC ligand; nevertheless, it also positively selected many T cells that could react with this ligand. Some of the TCRs on the selected T cells were related to those on cells from normal mice and some were not. IEk bound to the Hb variant, on the other hand, did not select any T cells which could react with IEk + MCC. These results demonstrate that although positive selection is a partially degenerate event, the sequence of the peptide involved in positive selection controls the selected repertoire.

Show MeSH
Thymus and spleen cells from 72ATg and 99ATg mice  present exogenous peptides poorly. Thymus and spleen cells were isolated  from various types of mice as described in Materials and Methods. They  were cultured with different concentrations of Hb and a T cell hybridoma, KH-8.3, specific for IEk + Hb. The ability of the cells to present  the exogenously added peptide was assayed by measurement of production of IL-2 by the T cell hybridoma 24 h later. The results are representative of at least three independent experiments.
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Figure 2: Thymus and spleen cells from 72ATg and 99ATg mice present exogenous peptides poorly. Thymus and spleen cells were isolated from various types of mice as described in Materials and Methods. They were cultured with different concentrations of Hb and a T cell hybridoma, KH-8.3, specific for IEk + Hb. The ability of the cells to present the exogenously added peptide was assayed by measurement of production of IL-2 by the T cell hybridoma 24 h later. The results are representative of at least three independent experiments.

Mentions: Staining experiments of this type did not reveal whether or not the IE proteins in the 99ATg and 72ATg mice were still bound to the covalent peptides with which they had been engaged genetically. To find out whether displacement with other peptides had occurred, cells from the transgenic mice were tested for their ability to present exogenously added peptides to T cells specific for IEk bound to the exogenous peptide. Thymus and spleen cells from the 99ATg mice presented exogenous peptides very poorly (Fig. 2). By contrast, thymus and spleen cells from the IEwtTg animals presented peptide fairly well, and thymus and spleen cells from B10.BR animals had very good activity.


Selection of antigen-specific T cells by a single IEk peptide combination.

Liu CP, Parker D, Kappler J, Marrack P - J. Exp. Med. (1997)

Thymus and spleen cells from 72ATg and 99ATg mice  present exogenous peptides poorly. Thymus and spleen cells were isolated  from various types of mice as described in Materials and Methods. They  were cultured with different concentrations of Hb and a T cell hybridoma, KH-8.3, specific for IEk + Hb. The ability of the cells to present  the exogenously added peptide was assayed by measurement of production of IL-2 by the T cell hybridoma 24 h later. The results are representative of at least three independent experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2199109&req=5

Figure 2: Thymus and spleen cells from 72ATg and 99ATg mice present exogenous peptides poorly. Thymus and spleen cells were isolated from various types of mice as described in Materials and Methods. They were cultured with different concentrations of Hb and a T cell hybridoma, KH-8.3, specific for IEk + Hb. The ability of the cells to present the exogenously added peptide was assayed by measurement of production of IL-2 by the T cell hybridoma 24 h later. The results are representative of at least three independent experiments.
Mentions: Staining experiments of this type did not reveal whether or not the IE proteins in the 99ATg and 72ATg mice were still bound to the covalent peptides with which they had been engaged genetically. To find out whether displacement with other peptides had occurred, cells from the transgenic mice were tested for their ability to present exogenously added peptides to T cells specific for IEk bound to the exogenous peptide. Thymus and spleen cells from the 99ATg mice presented exogenous peptides very poorly (Fig. 2). By contrast, thymus and spleen cells from the IEwtTg animals presented peptide fairly well, and thymus and spleen cells from B10.BR animals had very good activity.

Bottom Line: Some of the TCRs on the selected T cells were related to those on cells from normal mice and some were not.IEk bound to the Hb variant, on the other hand, did not select any T cells which could react with IEk + MCC.These results demonstrate that although positive selection is a partially degenerate event, the sequence of the peptide involved in positive selection controls the selected repertoire.

View Article: PubMed Central - PubMed

Affiliation: Howard Hughes Medical Institute, National Jewish Medical and Research Center, Denver, Colorado 80206, USA.

ABSTRACT
In normal mice, major histocompatibility complex (MHC) proteins are bound to many different peptides, derived from the proteins of their host. In the thymus, the diversity of this collection of MHC + peptide ligands allows thymocytes bearing many different T cell receptors (TCRs) to mature by low avidity reactions between the MHC + peptide ligands and the thymocyte TCRs. To investigate this problem, the selection of T cells specific for a well-studied combination of MHC + peptide, IEk + moth cytochrome c 88-103 (MCC), was investigated. Mice were created that expressed IEk bound to a single peptide, either a variant of MCC in which a critical TCR contact residue, 99K, was changed to A, or a variant of a mouse hemoglobin 64-76 (Hb) peptide, 72A. IEk bound to the MCC variant caused the clonal deletion of some T cells specific for the IEk + MCC ligand; nevertheless, it also positively selected many T cells that could react with this ligand. Some of the TCRs on the selected T cells were related to those on cells from normal mice and some were not. IEk bound to the Hb variant, on the other hand, did not select any T cells which could react with IEk + MCC. These results demonstrate that although positive selection is a partially degenerate event, the sequence of the peptide involved in positive selection controls the selected repertoire.

Show MeSH