The subtle interplay between gamma delta T lymphocytes and dendritic cells: is there a role for a therapeutic cancer vaccine in the era of combinatorial strategies?

γδ T cells in autoimmune uveitis pathogenesis: A promising therapeutic target

Autoimmune uveitis is a non-infectious, inflammatory intraocular disease that affects the uveal and adjacent tissues. It frequently causes varying degrees of visual loss. Evidence for the strong association between activated γδ T cells and the development of autoimmune uveitis is growing. The innate and adaptive immune response are connected in the early phases by the γδ T cells that contain the γ and δ chains. γδ T cells can identify antigens in a manner that is not constrained by the MHC. When activated by various pathways, γδ T cells can not only secrete pro-inflammatory factors early on (such as IL-17), but they can also promote Th17 cells responses, which ultimately exacerbates autoimmune uveitis. Therefore, we review the mechanisms by which γδ T cells affect autoimmune uveitis in different activation and disease states. Moreover, we also prospect for immunotherapies targeting different γδ T cell-related action pathways, providing a reference for exploring new drug for the treatment of autoimmune uveitis.

γδT cells in oral tissue immune surveillance and pathology

The oral mucosa's immune system is composed of tissue-resident and specifically recruited leukocytes that could effectively tolerate a wide range of microbial and mechanical assaults. Shortly after CD4⁺ helper T cells (TH17 cells) that produce interleukin 17 (IL-17) were identified, it was discovered that γδT cells could also induce substantial levels of this pro-inflammatory cytokine. In the past decades, it has become clear that due to a complicated thymic program of development, γδT cells frequently serve as the primary sources of IL-17 in numerous models of inflammatory diseases while also assisting in the maintenance of tissue homeostasis in the skin and intestine. But it wasn't until recently that we took thorough insight into the complex features of γδT cells in the oral mucosa. Most gingival intraepithelial γδT cells reside in the junctional epithelium adjacent to the dental biofilm, suggesting their potential role in regulating oral microbiota. However, inconsistent results have been published in this regard. Similarly, recent findings showed contradictory data about the role of γδT lymphocytes in experimental periodontitis based on different models. In addition, conflicting findings were presented in terms of alveolar bone physiology and pathology underlying the oral mucosa. This review provided an overview of current knowledge and viewpoints regarding the complex roles played by oral-resident γδT cells in host-microbiota interactions, gingivitis and periodontitis, bone physiology and pathology.

γδ T Lymphocytes as a Double-Edged Sword-State of the Art in Gynecological Diseases

Human gamma-delta (γδ) T cells are a heterogeneous cell population that bridges the gap between innate and acquired immunity. They are involved in a variety of immunological processes, including tumor escape mechanisms. However, by being prolific cytokine producers, these lymphocytes also participate in antitumor cytotoxicity. Which one of the two possibilities takes place depends on the tumor microenvironment (TME) and the subpopulation of γδ T lymphocytes. The aim of this paper is to summarize existing knowledge about the phenotype and dual role of γδ T cells in cancers, including ovarian cancer (OC). OC is the third most common gynecological cancer and the most lethal gynecological malignancy. Anticancer immunity in OC is modulated by the TME, including by immunosuppressive cells, cytokines, and soluble factors. Immune cells are exposed in the TME to many signals that determine their immunophenotype and can manipulate their functions. The significance of γδ T cells in the pathophysiology of OC is enigmatic and remains to be investigated.

γδ T Cells in the Tumor Microenvironment-Interactions With Other Immune Cells

A growing number of studies have shown that γδ T cells play a pivotal role in mediating the clearance of tumors and pathogen-infected cells with their potent cytotoxic, cytolytic, and unique immune-modulating functions. Unlike the more abundant αβ T cells, γδ T cells can recognize a broad range of tumors and infected cells without the requirement of antigen presentation via major histocompatibility complex (MHC) molecules. Our group has recently demonstrated parts of the mechanisms of T-cell receptor (TCR)-dependent activation of Vγ9Vδ2+ T cells by tumors following the presentation of phosphoantigens, intermediates of the mevalonate pathway. This process is mediated through the B7 immunoglobulin family-like butyrophilin 2A1 (BTN2A1) and BTN3A1 complexes. Such recognition results in activation, a robust immunosurveillance process, and elicits rapid γδ T-cell immune responses. These include targeted cell killing, and the ability to produce copious quantities of cytokines and chemokines to exert immune-modulating properties and to interact with other immune cells. This immune cell network includes αβ T cells, B cells, dendritic cells, macrophages, monocytes, natural killer cells, and neutrophils, hence heavily influencing the outcome of immune responses. This key role in orchestrating immune cells and their natural tropism for tumor microenvironment makes γδ T cells an attractive target for cancer immunotherapy. Here, we review the current understanding of these important interactions and highlight the implications of the crosstalk between γδ T cells and other immune cells in the context of anti-tumor immunity.

Fluorescent Artificial Antigens Revealed Extended Membrane Networks Utilized by Live Dendritic Cells for Antigen Uptake

Dendritic cells (DCs) can infiltrate tight junctions of the epithelium to collect remote antigens during immune surveillance. While elongated membrane structures represent a plausible structure to perform this task, their functional mechanisms remain elusive owing to the lack of high-resolution characterizations in live DCs. Here, we developed fluorescent artificial antigens (FAAs) based on quantum dots coated with polyacrylic acid. Single-particle tracking of FAAs enables us to superresolve the membrane fiber network responsible for the antigen uptake. Using the DC2.4 cell line as a model system, we discovered the extensive membrane network approaching 200 μm in length with tunnel-like cavities about 150 nm in width. The membrane fiber network also contained heterogeneous circular migrasomes. Disconnecting the membrane network from the cell body decreased the intracellular FAA density. Our study enables mechanistic investigations of DC membrane networks and nanocarriers that target this mechanism.

Research progress on dendritic cell vaccines in cancer immunotherapy

Dendritic cell (DC) vaccines induce specific immune responses that can selectively eliminate target cells. In recent years, many studies have been conducted to explore DC vaccination in the treatment of hematological malignancies, including acute myeloid leukemia and myelodysplastic syndromes, as well as other nonleukemia malignancies. There are at least two different strategies that use DCs to promote antitumor immunity: in situ vaccination and canonical vaccination. Monocyte-derived DCs (mo-DCs) and leukemia-derived DCs (DCleu) are the main types of DCs used in vaccines for AML and MDS thus far. Different cancer-related molecules such as peptides, recombinant proteins, apoptotic leukemic cells, whole tumor cells or lysates and DCs/DCleu containing a vaster antigenic repertoire with RNA electroporation, have been used as antigen sources to load DCs. To enhance DC vaccine efficacy, new strategies, such as combination with conventional chemotherapy, monospecific/bispecific antibodies and immune checkpoint-targeting therapies, have been explored. After a decade of trials and tribulations, much progress has been made and much promise has emerged in the field. In this review we summarize the recent advances in DC vaccine immunotherapy for AML/MDS as well as other nonleukemia malignancies.

CCR2 and PTPRC are regulators of tumor microenvironment and potential prognostic biomarkers of lung adenocarcinoma

Background

Tumor microenvironment (TME) plays an essential role in lung adenocarcinoma (LUAD) development and metastasis. With the development of TME research, it has been proved that differences in tumor-infiltrating immune cells (TICs) and gene expression profile are related to the prognosis of cancer. The aim of our study was to identify key genes affecting immune state in TME of LUAD.

Methods

The RNA-seq data and clinical characteristics of 594 LUAD patients were downloaded from the TCGA database. ImmuneScore, StromalScore and ESTIMATEScore of each LUAD sample were calculated using ESTIMATE algorithm. Based on the median of different scores, LUAD samples were divided into high and low score groups. Differentially expressed genes (DEGs) between groups were obtained, and univariate Cox regression analysis and protein-protein interaction (PPI) network were used to screen the shared DEGs generating in the intersection analysis. Finally, the CIBORSORT algorithm was performed to calculate the relative contents of TICs for each LUAD sample, and the correlation analysis between TICs and key genes was used to determine the influence of key genes to the TME.

Results

In the presented study, we found that three different scores were positively correlated with the prognosis of LUAD patients, and correlation analysis showed the different scores were closely related to tumor progression and metastasis. After performing the intersection analysis, a total of 585 up-regulated and 107 down-regulated DEGs between the high and low score groups were obtained, all of which were enriched in immune-related functions. Having used univariate COX regression analysis and PPI network, the key genes, CCR2 and PTPRC, affecting the immune status of TME and the prognosis of LUAD were acquired. Analysis based on the CIBERSORT algorithm suggested that CCR2 and PTPRC were correlated with a variety of TICs, and closely related to the clinical characteristics of the LUAD patients.

Conclusions

Our research showed that CCR2 and PTPRC may be potential prognostic markers in LUAD, which may affect the function of γδT cells and other immune cells by participating in the regulation of TME immune state.

Dendritic Cells Are the Intriguing Players in the Puzzle of Idiopathic Pulmonary Fibrosis Pathogenesis

Idiopathic pulmonary fibrosis (IPF) is the most devastating progressive interstitial lung disease that remains refractory to treatment. Pathogenesis of IPF relies on the aberrant cross-talk between injured alveolar cells and myofibroblasts, which ultimately leads to an aberrant fibrous reaction. The contribution of the immune system to IPF remains not fully explored. Recent evidence suggests that both innate and adaptive immune responses may participate in the fibrotic process. Dendritic cells (DCs) are the most potent professional antigen-presenting cells that bridge innate and adaptive immunity. Also, they exert a crucial role in the immune surveillance of the lung, where they are strategically placed in the airway epithelium and interstitium. Immature DCs accumulate in the IPF lung close to areas of epithelial hyperplasia and fibrosis. Conversely, mature DCs are concentrated in well-organized lymphoid follicles along with T and B cells and bronchoalveolar lavage of IPF patients. We have recently shown that all sub-types of peripheral blood DCs (including conventional and plasmacytoid DCs) are severely depleted in therapy naïve IPF patients. Also, the low frequency of conventional CD1c⁺ DCs is predictive of a worse prognosis. The purpose of this mini-review is to focus on the main evidence on DC involvement in IPF pathogenesis. Unanswered questions and opportunities for future research ranging from a better understanding of their contribution to diagnosis and prognosis to personalized DC-based therapies will be explored.