International immunology最新文献

Lymphocyte homing to peripheral lymph nodes (PLN) is critical for immune surveillance. However, autoimmune diseases such as multiple sclerosis (MS) can occur due to excessive immune responses in the PLN. Here we show that 6-sulfo sialyl Lewis X (6-sulfo sLex) glycans on high endothelial venules that function as ligands for l-selectin on lymphocytes play a critical role in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), an animal model of MS. In N-acetylglucosamine-6-O-sulfotransferase (GlcNAc6ST)-1 and GlcNAc6ST-2 double-knockout mice lacking the expression of 6-sulfo sLeX glycans, the EAE symptoms and the numbers of effector Th1 and Th17 cells in the draining lymph nodes (dLN) and spinal cords (SC) were significantly reduced. To determine whether 6-sulfo sLeX could serve as a target for MS, we also examined the effects of anti-glycan monoclonal antibody (mAb) SF1 against 6-sulfo sLeX in EAE. Administration of mAb SF1 significantly reduced EAE symptoms and the numbers of antigen-specific effector T cells in the dLN and SC in association with suppression of critical genes including Il17a and Il17f that are involved in the pathogenesis of EAE. Taken together, these results suggest that 6-sulfo sLeX glycan would serve as a novel target for MS.

Previous observational and experimental studies have suggested a relationship between statin treatments and the augmentation of immunotherapy effects; however, the causal role of statin usage in promoting antitumor immunity remains largely unexplored. Utilizing large-scale genome-wide association studies, we conducted a Mendelian Randomization (MR) analysis to examine the association between genetically proxied inhibition of the gene for 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), a specific target of statins, and 524 immunotherapy-related profiles, encompassing immune cells, inflammatory cytokines, immune checkpoints, and gut microbiota. Our findings indicated a suggestive association between statin therapy and proinflammatory as well as antitumor effects; notably, inhibition of HMGCR demonstrated a robust link with increased susceptibility of various immune cell types, including basophil cells, white blood cells, eosinophil cells, neutrophil cells, activated CD8+ T cells, dendritic cells, and natural killer cells; furthermore, a causal relationship was observed between statin use and a decrease in terminal CD8+ T cells, granulocytes, monocytes, and myeloid-derived suppressor cells; genetically proxied statin usage was also significantly associated with elevated levels of proinflammatory cytokines and immunotherapy-related gut microbiota; importantly, the potential inhibition of HMGCR in influencing the response to immunotherapy was confirmed in the real-world cohorts. This study provides novel insights into the regulatory role of HMGCR inhibition in antitumor immunity, suggesting that strategies targeting HMGCR or lipid regulation may hold therapeutic potential for enhancing the efficacy of immunotherapy.

Adoptive cell therapy (ACT) is an immunotherapeutic approach that involves isolating T cells from a patient, culturing them ex vivo, then reinfusing the cells back into the patient. Although this strategy has shown remarkable efficacy in hematological malignancies, the solid-tumour microenvironment (TME) has presented serious challenges for therapy efficacy. Particularly, the TME has immunosuppressive signalling and presents a metabolically challenging environment that leads to T-cell suppression. T-cell metabolism is an expanding field of research with a focus on understanding its inherent link to T-cell function. Here, we review the current model of T-cell metabolism from naïve cells through effector and memory life stages, as well as updates to the model from recent literature. These models of metabolism have provided us with the tools and understanding to explore T-cell metabolic and mitochondrial insufficiency in the TME. We discuss manipulations that can be made to these mitochondrial and metabolic pathways to enhance the persistence of infused T cells, overcome the metabolically challenging TME and improve the efficacy of therapy in ACT models. Further understanding and investigation of the impact of metabolic pathways on T-cell performance could contribute to improving therapy efficacy for patients.

C-type lectin receptors (CLRs) are a family of pattern recognition receptors, which detect a broad spectrum of ligands via small carbohydrate-recognition domains (CRDs). CLEC12A is an inhibitory CLR that recognizes crystalline structures such as monosodium urate crystals. CLEC12A also recognizes mycolic acid, a major component of mycobacterial cell walls, and suppresses host immune responses. Although CLEC12A could be a therapeutic target for mycobacterial infection, structural information on CLEC12A was not available. We report here the crystal structures of human CLEC12A (hCLEC12A) in ligand-free form and in complex with 50C1, its inhibitory antibody. 50C1 recognizes human-specific residues on the top face of hCLEC12A CRD. A comprehensive alanine scan demonstrated that the ligand-binding sites of mycolic acid and monosodium urate crystals may overlap with each other, suggesting that CLEC12A utilizes a common interface to recognize different types of ligands. Our results provide atomic insights into the blocking and ligand-recognition mechanisms of CLEC12A and leads to the design of CLR-specific inhibitors.

The epithelial barrier theory links the recent rise in chronic non-communicable diseases, notably autoimmune and allergic disorders, to environmental agents disrupting the epithelial barrier. Global pollution and environmental toxic agent exposure have worsened over six decades because of uncontrolled growth, modernization, and industrialization, affecting human health. Introducing new chemicals without any reasonable control of their health effects through these years has led to documented adverse effects, especially on the skin and mucosal epithelial barriers. These substances, such as particulate matter, detergents, surfactants, food emulsifiers, micro- and nano-plastics, diesel exhaust, cigarette smoke, and ozone, have been shown to compromise the epithelial barrier integrity. This disruption is linked to the opening of the tight-junction barriers, inflammation, cell death, oxidative stress, and metabolic regulation. Consideration must be given to the interplay of toxic substances, underlying inflammatory diseases, and medications, especially in affected tissues. This review article discusses the detrimental effect of environmental barrier-damaging compounds on human health and involves cellular and molecular mechanisms.