Guidelines and Advances in Basic and Applied Dendritic Cell Biology

Abstract

Dear Readers,

The Study Group Dendritic Cells (AKDC) of the German Society for Immunology (DGfI), established on September 28, 2016, during the 46th Annual Meeting in Hamburg, has become an essential forum for fostering high-quality research in dendritic cell (DC) and macrophage biology. With a current membership of 342, the group emphasizes rigorous scientific inquiry, methodological standardization, and active collaboration between young and established investigators.

The research interests of the AKDC cover a wide spectrum of topics within DC and macrophage biology, addressing fundamental issues from ontogeny and tissue homeostasis to T cell priming and immune regulation. Importantly, the research initiatives extend into translational applications, aiming to harness these cells in therapeutic strategies against cancer and autoimmune diseases. This integrated approach underscores the dual commitment to understanding the cellular mechanisms underpinning immune responses and translating these insights into clinical innovation.

A notable initiative that emerged from the activities of the AKDC is this special collection of articles on DCs. This collection compiles recent key developments and technical advances in the field, providing a critical resource for researchers to keep pace with emerging methodologies and conceptual frameworks. The series not only highlights advances in basic DC biology but also lays the groundwork for applied research, thereby serving as a bridge between laboratory discoveries and clinical application.

Central to the AKDC's contributions are the hands-on laboratory protocols (Guidelines) that standardize the preparation and analysis of DC subsets. One set of guidelines details the preparation of single-cell suspensions from mouse lymphoid tissues—including the spleen, lymph nodes, and thymus—and describes the subsequent multiparameter flow cytometry analysis designed to differentiate DC subsets from other myeloid cells. Complementary protocols address the preparation of single-cell suspensions from mouse nonlymphoid tissues, such as skin, intestine, lung, kidney, mammary glands, oral mucosa, and transplantable tumors, ensuring that a wide range of experimental systems can benefit from reproducible methodologies.

The guidelines further extend into human studies, where protocols for the preparation of single-cell suspensions from human lymphoid and nonlymphoid tissues are detailed. These protocols include detailed gating strategies for flow cytometric analysis and cell sorting, thereby enhancing the resolution at which primary human DC subpopulations can be examined. In addition, state-of-the-art protocols for multiparameter fluorescence microscopy have been developed to facilitate the visualization and quantitative analysis of DC subsets within tissue sections, further advancing our capacity to analyze these cells in situ.

Beyond these technical protocols, the article collection contains comprehensive reviews that critically evaluate various aspects of DC biology and clinical application. For example, one review contrasts Langerhans cells in the skin and oral mucosa, discussing similarities and differences in their development and function. Other reviews delve into the heterogeneity of classical DC2 subsets versus monocyte-derived DCs, the generation of DCs from induced pluripotent stem cells and through direct reprogramming of somatic cells, and the application of advanced mutant mouse models to decipher DC functions in vivo. Additional reviews focus on the ontogeny and functional specialization of human DC subsets, the current state of DC antigen targeting strategies for immunotherapy, and the differential activation profiles of circulating DCs and monocytes in the context of mild COVID-19 compared with yellow fever vaccination.

Finally, technical reports from the AKDC study group contribute to further strengthening the research landscape by introducing novel methodologies. These include protocols for generating fully functional monocytic myeloid-derived suppressor cells from conditionally immortalized HoxB8 cell lines, CRISPR/Cas9 editing strategies in these cells for targeted gene regulation studies, and the development of a 26-color flow cytometry panel for detailed immune phenotyping of murine DCs and other myeloid subtypes. Investigations into the regulation of DC metabolism by nitric oxide in murine GM-CSF cultures add another layer of mechanistic insight into DC bioenergetics.

Writing and preparing these comprehensive guidelines, reviews, and technical reports has been far more challenging than we anticipated at the beginning, not least as we started this project during the SARS-CoV-2 pandemic. We are extremely grateful to our collaborators, our authors, especially the lead authors who coordinated the various guideline topics, as well as our dedicated reviewers and editor Nadja Bakocevic for their tireless work in compiling this article collection. Written by some of the world's leading immunologists, we hope that these guidelines will provide useful resources for your daily laboratory work—promoting reproducibility, sparking innovation, and paving the way for translational advances in immunotherapy, while also serving as a reliable reference for current topics in DC and macrophage biology. We truly value your feedback on this comprehensive guidelines and article collection and invite you to share your thoughts or suggestions for future topics by emailing [email protected].

We look forward to hearing from you.

Björn E. Clausen & Diana Dudziak