7 research outputs found

    Development of triple-transgenic cells in hosts lacking MHC class I and II yields TCR<sup>int</sup>, single α-chain thymocytes.

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    <p>(A) Bone marrow from B6 mice was used to reconstitute irradiated CD45.1 (top) or MHC<sup>o/o</sup> (bottom) hosts. After eight weeks, thymocytes were harvested and analyzed for expression of either α-chain in TCR<sup>lo</sup>, TCR<sup>int</sup>, and TCR<sup>hi</sup>, Vβ5-positive gates. (B) Bone marrow from triple-transgenic mice was used to reconstitute irradiated CD45.1 (top) or MHC<sup>o/o</sup> (bottom) hosts. After eight weeks, thymocytes were harvested and analyzed for expression of either α-chain in TCR<sup>lo</sup>, TCR<sup>int</sup>, and TCR<sup>hi</sup>, Vβ5-positive gates. FACS plots representative of 7-9 mice per group in three independent experiments.</p

    Detection of dual Vα expressing cells in subsets gated based on Vα2-positive or Vα3.2-positive populations.

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    <p>Cells positive for subunits indicated above each plot were analyzed for the expression of the other subunit. Gates were set based on total lymphocyte population (gray lines). Top panel represents detection of dual Vα expressing cells by surface staining, bottom panel by intracellular staining. Results are representative of six mice per genotype.</p

    Vβ5 transgene skews expression of Vα2 from CD4 to CD8 subset, but Vα3.2 skews to CD8s with or without Vβ5 transgene.

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    <p>(A) LN cells from B6 mice (WT), <i>Tcra</i><sup>−/−</sup> mice transgenic for Vα2 and Vα3.2 miniloci, with or without transgenic rearranged Vβ5, were gated for Vα2 or Vα3.2 expression to show the assortment of cells to CD4 or CD8 subpopulations. FACS plots representative of >10 mice per genotype. (B) shows the CD8∶CD4 ratio of peripheral T cells from mouse strains expressing all the potential combinations of transgenes used here: Vα2 and Vα3.2 miniloci individually or together, and rearranged Vβ5 transgene. Data represent 8–17 mice per genotype.</p

    Vα3.2-expressing T cells are more frequent than Vα2-expressing cells in dual α-chain minilocus mice.

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    <p>(A) Vα2, Vα3.2 and Vβ5 expression in lymph node T cells from B6 mice (WT), <i>Tcra</i><sup>−/−</sup> mice transgenic for Vα2 or Vα3.2 miniloci, <i>Tcra</i><sup>−/−</sup> mice transgenic for both Vα2 and Vα3.2 miniloci, and <i>Tcra</i><sup>−/−</sup> mice transgenic for Vα2 and Vα3.2 miniloci plus the rearranged Vβ5 gene. FACS plots representative of >10 mice per genotype. (B) Ratio of Vα3: Vα2-bearing T cells in CD4 and CD8 peripheral T cell subsets in the mice strains described in (A). Data represent >10 mice per genotype.</p

    Triple-transgenic thymocytes exhibit efficient allelic exclusion of TCR Vα chains.

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    <p>(A) Double-negative (DN) and CD4 and CD8 single positive (SP) thymocytes from B6 (top), Vα2 Vα3.2 (middle) and Vα2 Vα3.2 Vβ5 (bottom) mice were analyzed for surface expression of Vα2, Vα3.2 and Vβ5 in TCR<sup>int</sup> and TCR<sup>hi</sup> gate. (B) DN and CD4 and CD8 SP thymocytes from B6 (top), Vα2 Vα3.2 (middle) and Vα2 Vα3.2 Vβ5 (bottom) mice were analyzed for intracellular expression of Vα2, Vα3.2 and Vβ5 in TCR<sup>int</sup> and TCR<sup>hi</sup> gate. FACS plots representative of >10 mice per genotype and are derived from the same dataset as <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0114320#pone-0114320-g004" target="_blank">Fig. 4</a>.</p

    data_sheet_1.docx

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    <p>A relatively high affinity/avidity of T cell receptor (TCR) recognition for self-peptide bound to major histocompatibility complex II (self-pMHC) ligands is a distinctive feature of CD4 T regulatory (Treg) cells, including their development in the thymus and maintenance of their suppressive functions in the periphery. Despite such high self-reactivity, however, all thymic-derived peripheral Treg populations are neither homogenous in their phenotype nor uniformly immune-suppressive in their function under steady state condition. We show here that based on the previously defined heterogeneity in the phenotype of peripheral Treg populations, Ly6C expression on Treg marks a lower degree of activation, proliferation, and differentiation status as well as functional incompetence. We also demonstrate that Ly6C expression on Treg in a steady state is either up- or downregulated depending on relative amounts of tonic TCR signals derived from its contacts with self-ligands. Interestingly, peripheral appearance and maintenance of these Ly6C-expressing Treg cells largely differed in an age-dependent manner, with their proportion being continuously increased from perinatal to young adult period but then being gradually declined with age. The reduction of Ly6C<sup>+</sup> Treg in the aged mice was not due to their augmented cell death but rather resulted from downregulation of Ly6C expression. The Ly6C downregulation was accompanied by proliferation of Ly6C<sup>+</sup> Treg cells and subsequent change into Ly6C<sup>−</sup> effector Treg with concomitant restoration of immune-suppressive activity. Importantly, we found that this phenotypic and functional change of Ly6C<sup>+</sup> Treg is largely driven by conventional effector T cell population. Collectively, these findings suggest a potential cross-talk between peripheral Treg subsets and effector T cells and provides better understanding for Treg homeostasis and function on maintaining self-tolerance.</p
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