A discrete population of IFN λ-expressing BDCA3hi dendritic cells is present in human thymus

Guidelines for DC preparation and flow cytometric analysis of human lymphohematopoietic tissues

This article is part of the Dendritic Cell Guidelines article series, which provides a collection of state-of-the-art protocols for the preparation, phenotype analysis by flow cytometry, generation, fluorescence microscopy, and functional characterization of mouse and human dendritic cells (DC) from lymphoid organs and various non-lymphoid tissues. Within this article, detailed protocols are presented that allow for the generation of single cell suspensions from human lymphohematopoietic tissues including blood, spleen, thymus, and tonsils with a focus on the subsequent analysis of DC via flow cytometry, as well as flow cytometric cell sorting of primary human DC. Further, prepared single cell suspensions as well as cell sorter-purified DC can be subjected to other applications including cellular enrichment procedures, RNA sequencing, functional assays, and many more. While all protocols were written by experienced scientists who routinely use them in their work, this article was also peer-reviewed by leading experts and approved by all co-authors, making it an essential resource for basic and clinical DC immunologists.

Insights into endotoxin-mediated lung inflammation and future treatment strategies

INTRODUCTION

Airway inflammatory disorders are prevalent diseases in need of better management and new therapeutics. Immunotherapies offer a solution to the problem of corticosteroid resistance. Areas covered: The current review focuses on lipopolysaccharide (Gram-negative bacterial endotoxin)-mediated inflammation in the lung and the animal models used to study related diseases. Endotoxin-induced lung pathology is usually initiated by antigen presenting cells (APC). We will discuss different subsets of APC including lung dendritic cells and macrophages, and their role in responding to endotoxin and environmental challenges. Expert commentary: The pharmacotherapeutic considerations to combat airway inflammation should cost-effectively improve quality of life with sustainable and safe strategies. Selectively targeting APCs in the lung offer the potential for a promising new strategy for the better management and treatment of inflammatory lung disease.

Molecular cloning and characterization of DNGR-1 in rhesus macaques

DC, NK lectin group receptor-1 (DNGR-1), also known as C-type lectin domain family 9 member A (CLEC9A), is a promising target for immunological therapeutics and vaccination against tumors and viruses. However, little is known about its property in rhesus macaques. In this study, we cloned rhesus macaque DNGR-1 cDNA, and found that its coding region could encode a 241-amino acid polypeptide with 91.7% sequence identity and similar antigenicity to that of humans. Both free and cell surface rhesus macaque DNGR-1 expressed in vitro could bind to apoptotic/dead cells induced by serum deprivation or freeze-thaw, and to pyroptotic cells stimulated with PMA and LPS. We also demonstrated that rhesus macaque DNGR-1 mRNA was present in all the examined tissues, with the highest in lymph nodes, spleen, blood, and thymus. The expression of DNGR-1 that is highly similar to that of humans warranted the usefulness of rhesus macaques in testing human therapeutics and vaccines targeting DNGR-1, especially those for HIV/AIDS.

Generation of mature T cells from human hematopoietic stem and progenitor cells in artificial thymic organoids

Studies of human T cell development require robust model systems that recapitulate the full span of thymopoiesis, from hematopoietic stem and progenitor cells (HSPCs) through to mature T cells. Existing in vitro models induce T cell commitment from human HSPCs; however, differentiation into mature CD3+TCRab+ single positive (SP) CD8+ or CD4+ cells is limited. We describe here a serum-free, artificial thymic organoid (ATO) system that supports highly efficient and reproducible in vitro differentiation and positive selection of conventional human T cells from all sources of HSPCs. ATO-derived T cells exhibited mature naïve phenotypes, a diverse TCR repertoire, and TCR-dependent function. ATOs initiated with TCR-engineered HSPCs produced T cells with antigen specific cytotoxicity and near complete lack of endogenous TCR Vβ expression, consistent with allelic exclusion of Vβ loci. ATOs provide a robust tool for studying human T cell development and stem cell based approaches to engineered T cell therapies.

Expression analysis of surface molecules on human thymic dendritic cells with the 10th HLDA Workshop antibody panel

Dendritic cells (DC) in the thymus have an important role in the establishment of central tolerance by promoting negative selection of autoreactive T cells and regulatory T-cell differentiation. Whereas human DC have recently been studied in various tissues in more detail, thymic DC subsets are still ill-defined. In the present work, we studied the binding of 71 monoclonal antibodies (mAb) submitted to the HLDA10 workshop to human CD123⁺ plasmacytoid DC and the two subsets of conventional DC (cDC, CD141⁺ and CD11b⁺) isolated from thymus tissue of infants undergoing corrective heart surgery. Within the panel, we found mAb binding to thymic pDC and both cDC subsets (for example, anti-Clec12A, TIM-3, Clec4A, CCR5, Axl, FLT3), but most of them additionally reacted with other thymic cell types. MAb directed to CD85h (ILT1) and the C-type lectin Clec7A (now CD369) reacted selectively with both cDC subsets, but not with other cells. Only one mAb directed to CD85g (ILT7) stained thymic pDC in a highly specific manner. Clec9A (DNGR1, now CD370) was the only tested HLDA10 antigen exclusively expressed on thymic CD141⁺ cDC. The present report summarizes all data obtained.