TCR signal strength controls thymic differentiation of discrete proinflammatory gamma delta T cell subsets

The mouse thymus produces discrete gd T cell subsets that make either interferon-g (IFN-g) or interleukin 17 (IL-17), but the role of the T cell antigen receptor (TCR) in this developmental process remains controversial. Here we show that Cd3g+/− Cd3d+/− (CD3 double-haploinsufficient (CD3DH)) mice have reduced TCR expression and signaling strength on gd T cells. CD3DH mice had normal numbers and phenotypes of ab thymocyte subsets, but impaired differentiation of fetal Vg6+ (but not Vg4+) IL-17- producing gd T cells and a marked depletion of IFN-g-producing CD122+ NK1.1+ gd T cells throughout ontogeny. Adult CD3DH mice showed reduced peripheral IFN-g+ gd T cells and were resistant to experimental cerebral malaria. Thus, TCR signal strength within specific thymic developmental windows is a major determinant of the generation of proinflammatory gd T cell subsets and their impact on pathophysiology

From Structure To Disease: Differential CD3 Usage In The Human and Mouse γδ T Cell Antigen Receptor Determines The Impact Of CD3 Deficiencies On T Cell Development

T cells are classified as belonging to the αβ or γδ lineage depending on which clonotypic heterodimer is incorporated into their T cell antigen receptor (TCR). Associated with αβ or γδ chains are the ζ homodimer and CD3 heterodimers, which are responsible for transducing signals across the plasma membrane into the cytoplasm, where signaling cascades ensue. The TCR is required for signaling governing such processes as development, differentiation and activation. Loss of any CD3 component leads to a block in αβ T cell development, as the signaling required for successful passage through various checkpoints becomes impaired. In mice, the CD3 subunit requirements for assembly and function of the γδTCR are different from those of the αβTCR. Recently, we have determined that they also differ between mouse and man. In this chapter, we discuss αβ and γδTCR composition and function, the novel assay we developed to determine TCR stoichiometries, and how these discoveries lead to a better understanding of CD3 deficiency phenotypes

Overlapping functions of human CD3δ and mouse CD3γ in αβ T-cell development revealed in a humanized CD3γ-deficient mouse

Humans lacking the CD3γ subunit of the pre-TCR and TCR complexes exhibit a mild αβ T lymphopenia, but have normal T cells. By contrast, CD3γ-deficient mice are almost devoid of mature αβ T cells due to an early block of intrathymic development at the CD4-CD8- double-negative (DN) stage. This suggests that in humans but not in mice, the highly related CD3δ chain replaces CD3γ during αβ T-cell development. To determine whether human CD3δ (hCD3δ) functions in a similar manner in the mouse in the absence of CD3γ, we introduced an hCD3δ transgene in mice that were deficient for both CD3δ and CD3γ, in which thymocyte development is completely arrested at the DN stage. Expression of hCD3δ efficiently supported pre-TCR-mediated progression from the DN to the CD4+CD8+ double-positive (DP) stage. However, αβTCR-mediated positive and negative thymocyte selection was less efficient than in wild-type mice, which correlated with a marked attenuation of TCR-mediated signaling. Of note, murine CD3γ-deficient TCR complexes that had incorporated hCD3δ displayed abnormalities in structural stability resembling those of T cells from CD3γ-deficient humans. Taken together, these data demonstrate that CD3δ and CD3γ play a different role in humans and mice in pre-TCR and TCR function during αβ T-cell development

Overlapping functions of human CD3δ and mouse CD3γ in αβ T-cell development revealed in a humanized CD3γ-deficient mouse

Humans lacking the CD3γ subunit of the pre-TCR and TCR complexes exhibit a mild αβ T lymphopenia, but have normal T cells. By contrast, CD3γ-deficient mice are almost devoid of mature αβ T cells due to an early block of intrathymic development at the CD4-CD8- double-negative (DN) stage. This suggests that in humans but not in mice, the highly related CD3δ chain replaces CD3γ during αβ T-cell development. To determine whether human CD3δ (hCD3δ) functions in a similar manner in the mouse in the absence of CD3γ, we introduced an hCD3δ transgene in mice that were deficient for both CD3δ and CD3γ, in which thymocyte development is completely arrested at the DN stage. Expression of hCD3δ efficiently supported pre-TCR-mediated progression from the DN to the CD4+CD8+ double-positive (DP) stage. However, αβTCR-mediated positive and negative thymocyte selection was less efficient than in wild-type mice, which correlated with a marked attenuation of TCR-mediated signaling. Of note, murine CD3γ-deficient TCR complexes that had incorporated hCD3δ displayed abnormalities in structural stability resembling those of T cells from CD3γ-deficient humans. Taken together, these data demonstrate that CD3δ and CD3γ play a different role in humans and mice in pre-TCR and TCR function during αβ T-cell development

Different composition of the human and mouse γδ T cell receptor explains diffferent phenotypes of CD3γ and CD3δ immunodeficiencies

The γδ T cell receptor for antigen (TCR) comprises the clonotypic TCRγδ, the CD3 (CD3γε and/or CD3δε), and the ζζ dimers. γδ T cells do not develop in CD3γ-deficient mice, whereas human patients lacking CD3γ have abundant peripheral blood γδ T cells expressing high γδ TCR levels. In an attempt to identify the molecular basis for these discordant phenotypes, we determined the stoichiometries of mouse and human γδ TCRs using blue native polyacrylamide gel electrophoresis and anti-TCR-specific antibodies. The γδ TCR isolated in digitonin from primary and cultured human γδ T cells includes CD3δ, with a TCRγδCD3ε2δγζ2 stoichiometry. In CD3γ-deficient patients, this may allow substitution of CD3γ by the CD3δ chain and thereby support γδ T cell development. In contrast, the mouse γδ TCR does not incorporate CD3δ and has a TCRγδCD3ε2γ2ζ2 stoichiometry. CD3γ-deficient mice exhibit a block in γδ T cell development. A human, but not a mouse, CD3δ transgene rescues γδ T cell development in mice lacking both mouse CD3δ and CD3γ chains. This suggests important structural and/or functional differences between human and mouse CD3δ chains during γδ T cell development. Collectively, our results indicate that the different γδ T cell phenotypes between CD3γ-deficient humans and mice can be explained by differences in their γδ TCR composition

Supplementary Material for: Human Invariant Natural Killer T Cells Respond to Antigen-Presenting Cells Exposed to Lipids from Olea europaea Pollen

<p><b><i>Background:</i></b> Allergic sensitization might be influenced by the lipids present in allergens, which can be recognized by natural killer T (NKT) cells on antigen-presenting cells (APCs). The aim of this study was<b> </b>to analyze the effect of olive pollen lipids in human APCs, including monocytes as well as monocyte-derived macrophages (Mϕ) and dendritic cells (DCs). <b><i>Methods:</i></b> Lipids were extracted from olive (<i>Olea europaea</i>) pollen grains. Invariant (i)NKT cells, monocytes, Mϕ, and DCs were obtained from buffy coats of healthy blood donors, and their cell phenotype was determined by flow cytometry. iNKT cytotoxicity was measured using a lactate dehydrogenase assay. Gene expression of <i>CD1A</i> and <i>CD1D</i> was performed by RT-PCR, and the production of IL-6, IL-10, IL-12, and TNF-α cytokines by monocytes, Mϕ, and DCs was measured by ELISA. <b><i>Results:</i></b> Our results showed that monocytes and monocyte-derived Mϕ treated with olive pollen lipids strongly activate iNKT cells. We observed several phenotypic modifications in the APCs upon exposure to pollen-derived lipids. Both Mϕ and monocytes treated with olive pollen lipids showed an increase in <i>CD1D</i> gene expression, whereas upregulation of cell surface CD1d protein occurred only in Mϕ. Furthermore, DCs differentiated in the presence of human serum enhance their surface CD1d expression when exposed to olive pollen lipids. Finally, olive pollen lipids were able to stimulate the production of IL-6 but downregulated the production of lipopolysaccharide- induced IL-10 by Mϕ. <b><i>Conclusions:</i></b> Olive pollen lipids alter the phenotype of monocytes, Mϕ, and DCs, resulting in the activation of NKT cells, which have the potential to influence allergic immune responses.</p

Humedales de la Orinoquia (Colombia-Venezuela)

La conservación de la inmensa diversidad biológica de la cuenca del Orinoco depende de nuestra voluntad y del conocimiento que tengamos de sus ecosistemas acuáticos, hasta hoy apenas descritos, siendo como son, abundantes y variados a lo largo del gradiente altitudinal. Ambientes temporales y permanentes; de aguas quietas, corrientes o torrentosas; blancas, claras o negras; naturales, creados o muy transformados por el hombre, conforman un mosaico heterogéneo que da vida a las alturas paramunas y a las cimas de los tepuyes, a los piedemontes, los Llanos, la Guayana y finalmente al Delta, en la unión salobre del río Orinoco con el océano Atlántico. Para el Instituto de Investigación de Recursos Biológicos Alexander von Humboldt la Orinoquia representa un área prioritaria y de especial interés en sus metas de investigación. Los talleres binacionales 2009-2011, auspiciaron la colaboración entre ambos países y dieron origen a proyectos como el que hoy presentamos. Un libro que reúne años de trabajo y observación en los humedales de esta cuenca, gracias al aporte de investigadores de Venezuela y Colombia cuyos datos, apuntes y análisis han servido para la identificación y descripción de las grandes regiones del Orinoco, su vegetación acuática y la tipología de sus aguas. Este nuevo volumen de la Serie de Recursos Hidrobiológicos y Pesqueros Continentales, identifica y homologa decenas de ambientes acuáticos o humedales que serán a partir de esta síntesis un valioso punto de referencia, que contribuirá sin duda alguna, al proceso de delimitación de los humedales continentales de Colombia.Bogotá, D. C., ColombiaInstituto de Investigación de Recursos Biológicos Alexander von Humbold

Primary T-cell immunodeficiency with functional revertant somatic mosaicism in CD247

Depto. de Inmunología, Oftalmología y ORLFac. de MedicinaTRUEMinisterio de Economía y Competitividad (MINECO)Instituto de Salud Carlos III (ISCIII)Comunidad de MadridFundacion LairUniversidad Complutense de Madridpu