New Discovery of Myeloid-Derived Suppressor Cell’s Tale on Viral Infection and COVID-19

Pancreatic cancer is a highly aggressive malignant tumor, that is becoming increasingly common in recent years. Despite advances in intensive treatment modalities including surgery, radiotherapy, biological therapy, and targeted therapy, the overall survival rate has not significantly improved in patients with pancreatic cancer. This may be attributed to the insidious onset, unknown pathophysiology, and poor prognosis of the disease. It is therefore essential to identify and develop more effective and safer treatments for pancreatic cancer. Tumor immunotherapy is the new and fourth pillar of anti-tumor therapy after surgery, radiotherapy, and chemotherapy. Significant progress has made in the use of immunotherapy for a wide variety of malignant tumors in recent years; a breakthrough has also been made in the treatment of pancreatic cancer. This review describes the advances in immune checkpoint inhibitors, cancer vaccines, adoptive cell therapy, oncolytic virus, and matrix-depletion therapies for the treatment of pancreatic cancer. At the same time, some new potential biomarkers and potential immunotherapy combinations for pancreatic cancer are discussed. The molecular mechanisms of various immunotherapies have also been elucidated, and their clinical applications have been highlighted. The current challenges associated with immunotherapy and proposed strategies that hold promise in overcoming these limitations have also been discussed, with the aim of offering new insights into immunotherapy for pancreatic cancer.

Section: New Immunotherapiesmentioning

confidence: 99%

Frontiers and future of immunotherapy for pancreatic cancer: from molecular mechanisms to clinical application

Zheng,

Liu,

Zhang

et al. 2024

“…Several studies have also reported elevated numbers of MDSCs in patients with chronic HIV infection, which dampen anti-HIV T-cell-mediated immune responses ( 152 , 153 ) and promote the development of Tregs ( 154 ). An increased frequency of MDSCs has been observed in the peripheral blood of patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), particularly those with severe disease ( 155 ). The expansion of MDSCs in SARS-CoV-2-infected patients appears to correlate with the severity of respiratory symptoms and the need for intensive care ( 155 ).…”

Section: Suppressive Mechanisms Of Mdscsmentioning

confidence: 99%

“…An increased frequency of MDSCs has been observed in the peripheral blood of patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), particularly those with severe disease ( 155 ). The expansion of MDSCs in SARS-CoV-2-infected patients appears to correlate with the severity of respiratory symptoms and the need for intensive care ( 155 ).…”

Section: Suppressive Mechanisms Of Mdscsmentioning

confidence: 99%

Mechanisms underlying immunosuppression by regulatory cells

Goldmann,

Nwofor,

Chen

et al. 2024

Regulatory cells, such as regulatory T cells (Tregs), regulatory B cells (Bregs), and myeloid-derived suppressor cells (MDSCs), play a crucial role in preserving immune tolerance and controlling immune responses during infections to prevent excessive immune activation. However, pathogens have developed strategies to hijack these regulatory cells to decrease the overall effectiveness of the immune response and persist within the host. Consequently, therapeutic targeting of these immunosuppressive mechanisms during infection can reinvigorate the immune response and improve the infection outcome. The suppressive mechanisms of regulatory cells are not only numerous but also redundant, reflecting the complexity of the regulatory network in modulating the immune responses. The context of the immune response, such as the type of pathogen or tissue involved, further influences the regulatory mechanisms involved. Examples of these immunosuppressive mechanisms include the production of inhibitory cytokines such as interleukin 10 (IL-10) and transforming growth factor beta (TGF-β) that inhibit the production of pro-inflammatory cytokines and dampen the activation and proliferation of effector T cells. In addition, regulatory cells utilize inhibitory receptors like cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein 1 (PD-1) to engage with their respective effector cells, thereby suppressing their function. An alternative approach involves the modulation of metabolic reprogramming in effector immune cells to limit their activation and proliferation. In this review, we provide an overview of the major mechanisms mediating the immunosuppressive effect of the different regulatory cell subsets in the context of infection.

“…It can be seen that M-MDSCs not only suppress the immune activity of T cells during the acute episode after SARS-CoV-2 infection, but also have a recall response to suppress T cells during the recovery period. In conclusion, the results of different studies may vary, but MDSCs exhibit different phenotypic characteristics and functional status with various stages of COVID-19, and MDSCs, as one of the key pathogenic factors of COVID-19 inflammation and immunosuppression, may be a major target for treatment ( 30 , 46 , 47 ).…”

Section: Mdscs As a Target For Infectious Lung Diseasesmentioning

confidence: 99%

Advances in the study of myeloid-derived suppressor cells in infectious lung diseases

Zhang

Yuan

2023

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature cells capable of inhibiting T-cell responses. MDSCs have a crucial role in the regulation of the immune response of the body to pathogens, especially in inflammatory response and pathogenesis during anti-infection. Pathogens such as bacteria and viruses use MDSCs as their infectious targets, and even some pathogens may exploit the inhibitory activity of MDSCs to enhance pathogen persistence and chronic infection of the host. Recent researches have revealed the pathogenic significance of MDSCs in pathogens such as bacteria and viruses, despite the fact that the majority of studies on MDSCs have focused on tumor immune evasion. With the increased prevalence of viral respiratory infections, the resurgence of classical tuberculosis, and the advent of medication resistance in common bacterial pneumonia, research on MDSCs in these illnesses is intensifying. The purpose of this work is to provide new avenues for treatment approaches to pulmonary infectious disorders by outlining the mechanism of action of MDSCs as a biomarker and therapeutic target in pulmonary infectious diseases.