Basic Techniques for Studies of iNKT Cells and MAIT Cells

Phenotypical and functional alteration of unconventional T cells in severe COVID-19 patients

Journal of Experimental Medicine ◽

10.1084/jem.20200872 ◽

2020 ◽

Vol 217 (12) ◽

Cited By ~ 13

Author(s):

Youenn Jouan ◽

Antoine Guillon ◽

Loïc Gonzalez ◽

Yonatan Perez ◽

Chloé Boisseau ◽

...

Keyword(s):

T Cells ◽

Cell Biology ◽

Potential Contribution ◽

Inkt Cells ◽

Mait Cells ◽

Phenotypic Alteration ◽

T Cell Biology ◽

Life Threatening ◽

Regulatory Functions ◽

Functional Alteration

COVID-19 includes lung infection ranging from mild pneumonia to life-threatening acute respiratory distress syndrome (ARDS). Dysregulated host immune response in the lung is a key feature in ARDS pathophysiology. However, cellular actors involved in COVID-19–driven ARDS are poorly understood. Here, in blood and airways of severe COVID-19 patients, we serially analyzed unconventional T cells, a heterogeneous class of T lymphocytes (MAIT, γδT, and iNKT cells) with potent antimicrobial and regulatory functions. Circulating unconventional T cells of COVID-19 patients presented with a profound and persistent phenotypic alteration. In the airways, highly activated unconventional T cells were detected, suggesting a potential contribution in the regulation of local inflammation. Finally, expression of the CD69 activation marker on blood iNKT and MAIT cells of COVID-19 patients on admission was predictive of clinical course and disease severity. Thus, COVID-19 patients present with an altered unconventional T cell biology, and further investigations will be required to precisely assess their functions during SARS–CoV-2–driven ARDS.

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Classical MHC expression by DP thymocytes impairs the selection of non-classical MHC restricted innate-like T cells

Nature Communications ◽

10.1038/s41467-021-22589-z ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Hristo Georgiev ◽

Changwei Peng ◽

Matthew A. Huggins ◽

Stephen C. Jameson ◽

Kristin A. Hogquist

Keyword(s):

T Cells ◽

Epithelial Cells ◽

Cell Types ◽

Inkt Cells ◽

Mhc I ◽

Mait Cells ◽

Mhc Molecules ◽

Mhc Ii ◽

Different Cell Types ◽

Selection Of

AbstractConventional T cells are selected by peptide-MHC expressed by cortical epithelial cells in the thymus, and not by cortical thymocytes themselves that do not express MHC I or MHC II. Instead, cortical thymocytes express non-peptide presenting MHC molecules like CD1d and MR1, and promote the selection of PLZF+ iNKT and MAIT cells, respectively. Here, we report an inducible class-I transactivator mouse that enables the expression of peptide presenting MHC I molecules in different cell types. We show that MHC I expression in DP thymocytes leads to expansion of peptide specific PLZF+ innate-like (PIL) T cells. Akin to iNKT cells, PIL T cells differentiate into three functional effector subsets in the thymus, and are dependent on SAP signaling. We demonstrate that PIL and NKT cells compete for a narrow niche, suggesting that the absence of peptide-MHC on DP thymocytes facilitates selection of non-peptide specific lymphocytes.

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Human iNKT and MAIT cells exhibit a PLZF-dependent proapoptotic propensity that is counterbalanced by XIAP

Blood ◽

10.1182/blood-2012-09-456095 ◽

2013 ◽

Vol 121 (4) ◽

pp. 614-623 ◽

Cited By ~ 68

Author(s):

Stéphane Gérart ◽

Sophie Sibéril ◽

Emmanuel Martin ◽

Christelle Lenoir ◽

Claire Aguilar ◽

...

Keyword(s):

T Cells ◽

Lymphocyte Subpopulations ◽

T Cell Homeostasis ◽

High Susceptibility ◽

Inkt Cells ◽

Mait Cells ◽

T Lymphocyte Subpopulations ◽

Elevated Expression ◽

Moderate Effect ◽

Invariant Natural Killer

Abstract Invariant natural killer (iNKT) T cells and mucosal-associated invariant T (MAIT) cells represent peculiar T-lymphocyte subpopulations with innate-like properties that differ from conventional T cells. iNKT are reduced in the primary immunodeficiency caused by mutations in the X-linked inhibitor of apoptosis (XIAP). By studying the mechanism of this depletion, we herein report that iNKT cells exhibit a high susceptibility to apoptosis that is not observed with conventional T cells. Elevated expression of caspases 3 and 7 accounts for the proapoptotic phenotype of iNKT cells, which is inhibited by XIAP although it exerts a moderate effect in conventional T cells. Similarly, MAIT cells exhibit a proapoptotic propensity with elevated expression of activated caspases and are decreased in XIAP-deficient individuals. Knockdown of the transcription factor PLZF/ZBTB-16, which is involved in the effector program of iNKT cells, diminishes their proapoptotic phenotype. Conversely, overexpression of PLZF/ZBTB-16 in conventional T cells leads to a proapoptotic phenotype. Our findings identify a previously unknown pathway of regulation of innate-like T-cell homeostasis depending on XIAP and PLZF. The proapoptotic feature of iNKT cells also gives a reliable explanation of their exhaustion observed in different human conditions including the XIAP immunodeficiency.

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Tissue-Resident Lymphocytes: Implications in Immunotherapy for Hepatocellular Carcinoma

International Journal of Molecular Sciences ◽

10.3390/ijms22010232 ◽

2020 ◽

Vol 22 (1) ◽

pp. 232

Author(s):

Ji Won Han ◽

Seung Kew Yoon

Keyword(s):

Hepatocellular Carcinoma ◽

Cell Population ◽

Tumor Immunity ◽

Checkpoint Inhibitors ◽

Γδ T Cells ◽

Treg Cells ◽

Inkt Cells ◽

Mait Cells ◽

Invariant Natural Killer

Hepatocellular carcinoma (HCC) is a hard-to-treat cancer. The recent introduction of immune checkpoint inhibitors (ICIs) provided viable options to treat HCC, but the response rate is currently not sufficient. Thus, a better understanding of ICI-responding cells within tumors is needed to improve outcomes of ICI treatment in HCC. Recently, tissue-resident memory T (TRM) cells were defined as a subset of the memory T cell population; this cell population is actively under investigation to elucidate its role in anti-tumor immunity. In addition, the role of other tissue-resident populations such as tissue resident regulatory T (Treg) cells, mucosal associated invariant T (MAIT) cells, γδ T cells, and invariant natural killer T (iNKT) cells in anti-tumor immunity is also actively being investigated. However, there is no study that summarizes recent studies and discusses future perspectives in terms of tissue resident lymphocytes in HCC. In this review, we summarize key features of tissue-resident lymphocytes and their role in the anti-tumor immunity. Additionally, we review recent studies regarding the characteristics of tissue-resident lymphocytes in HCC and their role in ICI treatment and other immunotherapeutic strategies.

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Thymic iNKT single cell analyses unmask the common developmental program of mouse innate T cells

Nature Communications ◽

10.1038/s41467-020-20073-8 ◽

2020 ◽

Vol 11 (1) ◽

Author(s):

S. Harsha Krovi ◽

Jingjing Zhang ◽

Mary Jessamine Michaels-Foster ◽

Tonya Brunetti ◽

Liyen Loh ◽

...

Keyword(s):

T Cells ◽

Single Cell ◽

Adapter Protein ◽

Inkt Cells ◽

Mait Cells ◽

Developmental Program ◽

Innate T Cells ◽

The Common ◽

Invariant Natural Killer ◽

Transcriptional Landscape

AbstractMost T lymphocytes leave the thymus as naïve cells with limited functionality. However, unique populations of innate-like T cells differentiate into functionally distinct effector subsets during their development in the thymus. Here, we profiled >10,000 differentiating thymic invariant natural killer T (iNKT) cells using single-cell RNA sequencing to produce a comprehensive transcriptional landscape that highlights their maturation, function, and fate decisions at homeostasis. Our results reveal transcriptional profiles that are broadly shared between iNKT and mucosal-associated invariant T (MAIT) cells, illustrating a common core developmental program. We further unmask a mutual requirement for Hivep3, a zinc finger transcription factor and adapter protein. Hivep3 is expressed in early precursors and regulates the post-selection proliferative burst, differentiation and functions of iNKT cells. Altogether, our results highlight the common requirements for the development of innate-like T cells with a focus on how Hivep3 impacts the maturation of these lymphocytes.

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MR1 uses an endocytic pathway to activate mucosal-associated invariant T cells

Journal of Experimental Medicine ◽

10.1084/jem.20072579 ◽

2008 ◽

Vol 205 (5) ◽

pp. 1201-1211 ◽

Cited By ~ 101

Author(s):

Shouxiong Huang ◽

Susan Gilfillan ◽

Sojung Kim ◽

Bruce Thompson ◽

Xiaoli Wang ◽

...

Keyword(s):

T Cells ◽

Antigen Presentation ◽

Mhc Class Ii ◽

Cell Activation ◽

Endocytic Pathway ◽

Inkt Cells ◽

Mait Cells ◽

Invariant T Cells ◽

Endocytic Compartments ◽

Mait Cell

Like CD1d-restricted iNKT cells, mucosal-associated invariant T cells (MAITs) are “innate” T cells that express a canonical TCRα chain, have a memory phenotype, and rapidly secrete cytokines upon TCR ligation. Unlike iNKT cells, MAIT cells require the class Ib molecule MHC-related protein I (MR1), B cells, and gut flora for development and/or expansion, and they preferentially reside in the gut lamina propria. Evidence strongly suggests that MAIT cell activation is ligand-dependent, but the nature of MR1 ligand is unknown. In this study, we define a mechanism of endogenous antigen presentation by MR1 to MAIT cells. MAIT cell activation was dependent neither on a proteasome-processed ligand nor on the chaperoning by the MHC class I peptide loading complex. However, MAIT cell activation was enhanced by overexpression of MHC class II chaperones Ii and DM and was strikingly diminished by silencing endogenous Ii. Furthermore, inhibiting the acidification of the endocytic compartments reduced MR1 surface expression and ablated MAIT cell activation. The importance of the late endosome for MR1 antigen presentation was further corroborated by the localization of MR1 molecules in the multivesicular endosomes. These findings demonstrate that MR1 traffics through endocytic compartments, thereby allowing MAIT cells to sample both endocytosed and endogenous antigens.

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