Repurposing of poly-gamma-glutamic acid, immunotherapeutic drug for cervical intraepithelial neoplasia 1, as covid-19 treatment

Covid-19 virus variants identified so far are due to viral genetic diversity, genetic evolution, and variable infectivity, suggesting that high infection rates and high mortality rates may be contributed by these mutations. And it has been reported that the targeting strategies for innate immunity should be less vulnerable to viral evolution, variant emergence and resistance. Therefore, the most effective solution to Covid-19 infection has been proposed to prevent and treat severe exacerbation of patients with moderate disease by enhancing human immune responses such as NK cell and T cell. In previous studies, we demonstrated for the first time that gamma-PGA induced significant antitumor activity and antiviral activity by modulating NK cell-mediated cytotoxicity. Especially intranasal administration of gamma-PGA was found to effectively induce protective innate and CTL immune responses against viruses and we found out that gamma-PGA can be an effective treatment for cervical intraepithelial neoplasia 1 through phase 2b clinical trial. In this study, the possibility of gamma-PGA as a Covid-19 immune modulating agent was confirmed by animal experiments infected with Covid-19 viruses. After oral administration of gamma-PGA 300mug/mouse once a day for 5 days in a K18-hACE2 TG mouse model infected with SARS-CoV-2 (NCCP 43326;original strain) and SARS-CoV-2 (NCCP 43390;Delta variant), virus titer and clinical symptom improvement were confirmed. In the RjHan:AURA Syrian hamster model infected with SARS-CoV-2 (NCCP 49930;Delta variant), 350 or 550 mug/head of gamma-PGA was administered orally for 10 days once a day. The virus for infection was administered at 5 x 104 TCID50, and the titer of virus and the improvement of pneumonia lesions were measured to confirm the effectiveness in terms of prevention or treatment. In the mouse model infected with original Covid-19 virus stain, the weight loss was significantly reduced and the survival rate was also improved by the administration of gamma-PGA. And gamma-PGA alleviated the pneumonic lesions and reduced the virus titer of lung tissue in mice infected with delta variant. In the deltavariant virus infected hamster model, gamma-PGA showed statistically significant improvement of weight loss and lung inflammation during administration after infection. This is a promising result for possibility of Covid-19 therapeutics along with the efficacy results of mouse model, suggesting gammaPGA can be therapeutic candidate to modulate an innate immune response for Covid-19.

Mechanism of interferon induction by cannabidiol (CBD) and analogues in lung cancer cells

CBD, an FDA approved drug for epilepsy, may have therapeutic potential for other diseases and is currently being tested for efficacy in cancer-related clinical trials. As the literature about CBD, especially in vitro reports, is often contradictory, increasing our understanding of its specific action on a molecular level will allow to determine whether CBD can become a useful therapy or exacerbates specific cancers in a context-dependent manner. Due to its relative lipophilicity, CBD is challenging to dispense at therapeutic concentrations;therefore, one goal is to identify cannabinoid congeners with greater efficacy and reduced drug delivery challenges. We recently showed that CBD activates interferons as a mechanism of inhibiting SARS-CoV-2 replication in lung carcinoma cells. As factors produced by the innate immune system, interferons have been implicated in both pro-survival and growth arrest and apoptosis signaling in cancer. Here we show that CBD induces interferon production and interferon stimulated genes (ISGs) through a mechanism involving NRF2 and MAVS in lung carcinoma cells. We also show that CBDV, which differs from CBD by 2 fewer aliphatic tail carbons, has limited potency, suggesting that CBD specifically interacts with one or more cellular proteins rather than having a non-specific effect. We also identified other CBD-related cannabinoids that are more effective at inducing ISGs. Taken together, these results characterize a novel mechanism by which CBD activates the innate immune system in lung cancer cells and identify related cannabinoids that have possible therapeutic potential in cancer treatment.

Glucosaminylmuramyl dipeptide efficacy in post-COVID-19 patient rehabilitation treatment.

The COVID-19 pandemic has altered people's lifestyles around the world. Prevention of recurrent episodes of the disease and mitigation of its consequences are especially associated with effective post-COVID-19 rehabilitation in patients. The aim of the study was to evaluate the effects of the drug Likopid (glucosaminylmuramyl dipeptide, GMDP) for post-COVID-19 rehabilitation in patients. Material and methods. Patients who recovered from mild to moderate COVID-19 (n=60, mean age 54+/- 11.7 years) were randomized into the observation group (n=30, 15 men and 15 women) who received 2 courses of Licopid (1 mg twice a day) and the comparison group (n=30, 15 men and 15 women). Analysis of the phenotypic and functional characteristics of the innate immune cellular factors was carried out before the start of immunomodulatory therapy, immediately after the end of the course, and also after 6 months observations. In order to assess the quality of life of all patients, we used the SF-36 Health Status Survey and the Hospital Anxiety and Depression Scale questionnaires. Results. During assessing the effect of immunomodulatory therapy on the parameters of innate immunity of patients at the stage of rehabilitation after COVID-19, an increase in the protective cytolytic activity of CD16+ and CD8+Gr+ cells, as well as a persistent increase in TLR2, TLR4 and TLR9 expression was found, which indicates the antigen recognition recovery and presentation at the level of the monocytic link of the immune system. The use of GMDP as an immunomodulatory agent resulted in an 8-fold reduction in the frequency and severity of respiratory infections due to an increase in the total monocyte count. As a result of assessing patients' quality of life against the background of the therapy, a positive dynamic in role functioning was revealed in patients. In the general assessment of their health status, an increase in physical and mental well-being was noted during 6 months of observation. The comparison group showed no improvement in the psychoemotional state. Discussion. The study demonstrated the effectiveness of GMDP immunomodulatory therapy in correcting immunological parameters for post-COVID-19 rehabilitation in patients. The data obtained are consistent with the previously discovered ability of GMDP to restore impaired functions of phagocytic cells and induce the expression of their surface activation markers, which in turn contributes to an adequate response to pathogens. Conclusion. The study revealed that the correction of immunological parameters with the use of GMDP in COVID-19 convalescents contributed not only to a decrease in the frequency and severity of respiratory infections, but also to an improvement in the psycho-emotional state of patients, and a decrease in anxiety and depression.Copyright © Eco-Vector, 2023. All rights reserved.

Knowledge of African Traditional Medicine System: Immunomodulation

African traditional medicine is one of the oldest forms of health-care system in the continent that has continued to be relevant. It is usually holistic, treating mind and body, and includes aromatherapy, bone setting, circumcision, herbs, homeopathy massaging, spiritual therapies, maternity care, psychiatric care, music therapy, and many more. It is a very old and culturally informed method of health management that humans have used against diseases that have threatened existence. More than 60,000 of the world's higher plant species can be found in sub-Saharan Africa and the Indian Ocean Islands. These are about one-fourth of the global total and less than the 8% of the medicinal plants sold internationally from Africa. This scarcity could be due to lack of data on the traditional uses of many African plants as the knowledge is transferred orally by storytellers and traditional healers though in recent times, there are some information in print. Immunomodulation is seen as an essential feature of immunotherapy whereby immune responses are provoked, heightened, decreased, or avoided. Immune responses have been observed to be either cellular co-receptor expression, class switching, cytokine secretion, histamine release, immunoglobulin secretion, lymphocyte expression, or phagocytosis. Immune system dysfunction is responsible for various diseases like allergies, asthmas, arthritis, cancers, and infectious diseases. So modulation of immune responses is required in controlling diseases. This is requisite nowadays because of the upsurge of infectious diseases like superbugs caused by Multi-Resistant Staphylococcus aureus (MRSA) and the coronavirus (COVID-19) plus other emerging diseases. The historical view of African Traditional Medicine (ATMs) will be discussed from the point of view of specific plants used for immunomodulation in the ATMs and their efficacies following the trend of use and development of herbal medicines from crude formulations to refined dosage forms and procedures over time. Most of the ATMs are prepared as tonics and bitters to heighten and keep up immune defenses. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022.

PROTEIN SIGNALING MOLECULES AFFECTING THE DEVELOPMENT OF INNATE IMMUNITY MECHANISMS

The principle protein molecules (interferon gene stimulator, adapter proteins, B-cell lymphoma 2 proteins, zinc-finger antiviral protein, and others), mechanisms of apoptosis, necroptosis, perforation of plasma membranes with kinase-like proteins of a mixed line, and ribonucleic acid neutralization, which ensure the development of innate immunity, are described. The main defense mechanisms that viruses have developed at the various stages of evolution are considered. The features of the development of the mechanisms of apoptosis and autophagy in a new coronavirus infection, which are associated with increased secretion of pro-inflammatory cytokines and chemokines, leading to severe damage to host cells, are given. It has been found that serum levels of several proteins formed during autophagy caused by SARS-CoV-2 can be used to predict disease severity. These include a protein associated with microtubules 1A/1B, a protein of sequestoma 1, and a protein of the cellular system of autophagy ― beclin-1. The multifaceted role of interferons in the inhibition of viral infection and the features of the violation of the activating functions of interferons in coronavirus infection are described. The article can be used under the CC BY-NC-ND 4.0 license © Authors, 2022.

Prevention of vitamin D deficiency in children. The state of the problem in the world and in Ukraine.

The article presents current data on the prevalence of vitamin D deficiency and criteria for its deficiency in children in different countries. Vitamin D is recognized as one of the most important vitamins involved in many biochemical processes in the body. Its active metabolites play a key role in calcium absorption, bone mineralization and promote phosphate and magnesium metabolism. At the same time, in addition to affecting mineral metabolism, there is a wide range of conditions in which vitamin D also plays a preventive role. Vitamin D has been shown to play a vital role in innate immunity maintenance and is important in prevention of several diseases, including infections, autoimmune diseases, certain forms of cancer, type 1 and 2 diabetes, and cardiovascular diseases. Vitamin D is of particular importance for newborns and young children. This vitamin is involved in important physiological regulatory processes such as bone metabolism, lung development, maturation of the immune system and differentiation of the nervous system. Vitamin D deficiency increases risks of neonatal sepsis, necrotizing enterocolitis, respiratory distress syndrome, and bronchopulmonary dysplasia. Adequate intake of vitamin D and calcium during childhood can reduce the risk of osteoporosis and other diseases associated with vitamin D deficiency in adults. Recently, vitamin D deficiency has shown to be a potential risk factor for COVID-19 propensity. It has been established that to date most scientific pediatric societies have recognized the need to prevent vitamin D deficiency in healthy children of all ages, but data on the dosage of vitamin D in its prophylactic use differ. Most scientific societies recommend an average of 400-600 IU per day of vitamin D for prophylactic purposes. The analysis of published data shows the need to follow a strategy based on an individual approach, taking into account physiological characteristics, individual requirements and lifestyle.Copyright © 2021 University of Tartu Press. All rights reserved.

Nutrition Strategies Pre-infection, during, and Post-infection with Coronavirus Disease

Coronavirus disease is a serious viral infection that is characterized by severe inflammation and lymphopenia. The virus attacks many organs causing acute respiratory distress and malfunctioning of the organs leading to death. Through strengthening of the innate immune system, a balanced diet plays a critical role in defense against bacterial and viral diseases. A healthy diet before, during and after an infection can lessen the severity of the symptoms and speed up the recovery of damaged cells. Due to the Mediterranean diet's high concentration of bioactive polyphenols, which have antioxidant, anti-inflammatory, and antithrombic properties, numerous studies have suggested that it is a preventative dietary strategy against many diseases including coronavirus disease. Nutrition and herbal plants play a key role to enhance the immunity of people to protect and fight against coronavirus. Diet rich in antioxidants and phytochemicals represents perfect barrier to the virus through elevation of the innate immunity of the body. In addition, gut microbiota including prebiotics, probiotics, and synbiotics were found to enhance immunity to reduce the symptoms of the disease during infection. Protein-rich foods and honey bee products reported significant role during and post-coronavirus infection. This review presents updated information from original pre-clinical and clinical researches, and review articles as well to expose the nutritive strategies including breastfeeding benefits to infants pre-infection, during, and post-infection with coronavirus.Copyright © 2023, Scientific Foundation SPIROSKI. All rights reserved.

Messenger RNA Nanovaccine in Cancer Immunotherapy

During the past 2 years, messenger RNA (mRNA) nanovaccine has shown its remarkable antiviral efficacy, rapid manufacture, and good safety profile for preventing coronavirus infection. Meanwhile, intracellular delivery of mRNA-based cancer vaccine starts to show great potential to elicit antitumor immunity. mRNA encoding tumor antigens, delivery vehicles, and immune adjuvants are the key components of mRNA cancer vaccine. To achieve robust antitumor efficacy, mRNA encoding tumor antigens need to be efficiently delivered and translated in dendritic cells with concurrent innate immune stimulation to promote antigen presentation. Compared with other types of tumor vaccines, mRNA nanovaccine is featured by efficient antigen expression, high potential for rapid development, low-cost manufacture, and safe administration. In this chapter, we mainly focus on the mRNA synthesis, mRNA modification, delivery vectors with immune-stimulating features, and tumor antigen selection and discuss the future direction of mRNA nanovaccine in cancer immunotherapy. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2023.

Inherited deficiency of the OAS-RNase L pathway in children with MIS-C

Multisystem inflammatory syndrome in children (MIS-C) is a rare and severe condition that follows benign COVID-19. We report autosomal recessive deficiencies of OAS1, OAS2, or RNASEL in five unrelated children with MIS-C. The cytosolic dsRNA-sensing OAS1 and OAS2 generate 2'-5'-linked oligoadenylates (2-5A) that activate the ssRNA-degrading RNase L. Consistent with the absence of pneumonia in these patients, epithelial cells and fibroblasts defective for this pathway restricted SARS-CoV-2 normally. This contrasted with IFNAR1-deficient cells from patients prone to hypoxemic pneumonia without MIS-C. Monocytic cell lines and primary myeloid cells with OAS1, OAS2, or RNASEL deficiencies produce excessive amounts of inflammatory cytokines upon dsRNA or SARS-CoV- 2 stimulation. Exogenous 2-5A suppresses cytokine production in OAS1-but not RNase L- deficient cells. Cytokine production in RNase L-deficient cells is impaired by MDA5 or RIG-I deficiency and abolished by MAVS deficiency. Recessive OAS-RNase L deficiencies in these patients unleash the production of SARS-CoV-2-triggered, MAVS-mediated inflammatory cytokines by mononuclear phagocytes, thereby underlying MIS-C.Copyright © 2023 Elsevier Inc.

Altered immune response to vaccination in patients with plasma cell premalignancy

Introduction Patients with hematological malignancies, including multiple myeloma (MM), experience suboptimal responses to SARS-CoV-2 vaccination. Monoclonal Gammopathy of Undetermined Significance (MGUS) and Smoldering Multiple Myeloma (SMM) are precursors to MM and exhibit altered immune cell composition and function. The SARS-CoV-2 pandemic and the subsequent population-wide vaccination represent an opportunity to study the real-life immune response to a common antigen. Here, we present updated results from the IMPACT study, a study we launched in November 2020 to characterize the effect of plasma cell premalignancy on response to SARS-CoV2 vaccination (vx). Methods We performed: (i) ELISA for SARS-CoV-2-specific antibodies on 1,887 peripheral blood (PB) samples (237 healthy donors (HD), and 550 MGUS, 947 SMM, and 153 MM patients) drawn preand post-vx;(ii) single-cell RNA, T cell receptor (TCR), and B cell receptor (BCR) sequencing (10x Genomics) on 224 PB samples (26 HD, and 20 MGUS, 48 SMM, and 24 MM patients) drawn preand post-vx;(iii) plasma cytokine profiling (Olink) on 106 PB samples (32 HD, and 38 MGUS and 36 SMM patients) drawn pre- and post-vx;and (iv) bulk TCR sequencing (Adaptive Biotechnologies) on 8 PB samples from 4 patients (2 MGUS, 2 SMM) drawn pre- and post-vx. Results Patients with MGUS and SMM achieved comparable antibody titers to HD two months post-vx. However, patient titers waned significantly faster, and 4 months post-vx we observed significantly lower titers in both MGUS (Wilcoxon rank-sum, p=0.030) and SMM (p=0.010). These results indicate impaired humoral immune response in patients with MGUS and SMM.At baseline, the TCR repertoire was significantly less diverse in patients with SMM compared to HD (Wilcoxon rank-sum, p=0.039), while no significant difference was observed in the BCR repertoire (p=0.095). Interestingly, a significant increase in TCR repertoire diversity was observed post-vx in patients with SMM (paired t-test, p=0.014), indicating rare T cell clone recruitment in response to vaccination. In both HD and patients, recruited clones showed upregulation of genes associated with CD4+ naive and memory T cells, suggesting preservation of the T cell response in SMM, which was confirmed by bulk TCR-sequencing in 4 patients.Lastly, by cytokine profiling, we observed a defect in IL-1beta and IL-18 induction post-vx in patients with SMM compared to HD (Wilcoxon rank-sum, p=0.047 and p=0.015, respectively), two key monocyte-derived mediators of acute inflammation, suggesting an altered innate immune response as well. Conclusion Taken together, our findings highlight that despite the absence of clinical manifestations, plasma cell premalignancy is associated with defects in both innate and adaptive immune responses. Therefore, patients with plasma cell premalignancy may require adjusted vaccination strategies for optimal immunization.

Scientific rationale of Indian AYUSH Ministry advisory for COVID-19 prevention, prophylaxis, and immunomodulation

The current outbreak of COVID-19 is caused by the SARS-CoV-2 virus that has affected > 210 countries. Various steps are taken by different countries to tackle the current war-like health situation. In India, the Ministry of AYUSH released a self-care advisory for immunomodulation measures during the COVID-19 and this review article discusses the detailed scientific rationale associated with this advisory. Authors have spotted and presented in-depth insight of advisory in terms of immunomodulatory, antiviral, antibacterial, co-morbidity associated actions, and their probable mechanism of action. Immunomodulatory actions of advised herbs with no significant adverse drug reaction/toxicity strongly support the extension of advisory for COVID-19 prevention, prophylaxis, mitigations, and rehabilitation capacities. This advisory also emphasized Dhyana (meditation) and Yogasanas as a holistic approach in enhancing immunity, mental health, and quality of life. The present review may open-up new meadows for research and can provide better conceptual leads for future researches in immunomodulation, antiviral-development, psychoneuroimmunology, especially for COVID-19.Copyright © 2021, Institute of Korean Medicine, Kyung Hee University.

"Actionable" host genetic markers for repurposing "add-on therapy" in COVID-19

Background/Objectives: COVID-19 still represents a lifethreatening disease in individuals with a specific genetic background. We successfully applied a new Machine Learning method on WES data to extract a set of coding variants relevant for COVID- 19 severity. We aim to identify personalized add-on therapy. Method(s): A subset of identified variants, "actionable" by repurposed drugs, were functionally tested by in vitro and in vivo experiments. Result(s): Males with either rare loss of function variants in the TLR7 gene or L412F polymorphism in the TLR3 gene benefit from IFN-gamma, which is specifically defective in activated PBMCs, restoring innate immunity. Females heterozygous for rare variants in the ADAMTS13 gene and males with D603N homozygous polymorphism in the SELP gene benefit from Caplacizumab, which reduces vWF aggregation and thrombus formation. Males with either the low-frequency gain of function variant T201M in CYP19A1 gene or with poly-Q repeats >=23 in the AR gene benefit from Letrozole, an aromatase inhibitor, which restores normal testosterone levels, reducing inflammation and which rescues male golden hamsters from severe COVID-19. Conclusion(s): By adding these commonly used drugs to standard of care of selected patients, the rate of intubation is expected to decrease consistently, especially in patients with high penetrance rare genetic markers, mitigating the effect of the pandemic with a significant impact on the healthcare system.

Italian ancestral HLA haplotype predisposing to severe COVID-19 by low spike and high IFNalpha binding affinity

Background/Objectives: Validated association between COVID-19 and the most obvious candidate genes, e.g. HLA, is still missing. A weak association with class I HLA-C*04:01 was found for infection in Sardinians and for severity in another mixed population. Auto-antibodies to interferon type I have been implicated in the severity of COVID-19 in two studies. Method(s): The binding affinity between HLA molecules and SARS-CoV-2 spike protein and IFNalpha subunits was evaluated in silico. The presence of antibodies against one or more of the 12 IFNalpha subunits was evaluated in 160 hospitalized COVID-19 patients. The 10 most frequent haplotypes in the Italian population were tested in 1.997 SARS-CoV-2 infected patients (hospitalized versus not hospitalized). Result(s): The presence of auto-antibodies against at least one IFNalpha subunit was detected in 26% of patients. The haplotype A*24:02-B*35:02-C*04:01-DRB1*11:04-DQB1*03:01 was found to predispose to severity (p = 0.0018;p = 0.07 after Bonferroni correction) in patients <50 years. The haplotype includes alleles able to bind spike with low affinity (i.e. C*04:01 and DRB1*11:04) and IFNalpha with high affinity (i.e. DRB1*11:04). Conclusion(s): One of the 10 most frequent ancestral haplotype of the Italian population predisposes to severity likely reducing both innate immunity through IFNalpha auto-antibodies induction and adaptive immunity through weaker spike protein presentation.

POLYMORPHISMS OF LEUKOCYTE GENES HUMAN AND CONGENITAL ANTIGEN IMMUNITY ASSOCIATED WITH DIFFERENT THE SEVERITY OF THE COURSE OF THE NEW CORONAVIRUS INFECTIONS

The most significant single nucleotide human leukocyte antigen genes polymorphisms and innate immunity genes associated with varying degrees of acute respiratory infection severity are considered–COVID-19 caused by the SARS-CoV-2 coronavirus. As data accumulated, it became clear that the SARS-CoV-2 virus exhibits significant regional, ethnic, and individual specificity. This is due to the population groups' genetic characteristics. This is necessary to reliably know the human genotype relationship with the COVID-19 course severity (asymptomatic, mild, moderate, severe, and extremely severe up to fatal outcomes) for more successful therapy and vaccination. At the same time, it was also known that the innate immunity system is on the first line of defense against the pathogenic penetration into the body, and the human leukocyte antigen system encodes molecules of the same name on the surface of cells that present various antigens, including viral infection pathogens, and determine the severity of the course of many diseases;therefore, these systems' genes. This approach makes it possible to assess the likelihood of a severe and extremely severe disease course in healthy and infected people, which in turn contributes to the correct therapy strategy, pharmacotherapy, and vaccination, as well as to create new antiviral therapeutic and preventive medicines. The genetically determined immune response heterogeneity to SARS-CoV-2 infection requires further study, since there is no unambiguous opinion about the leading mechanism that determines disease severity. The article can be used under the CC BY-NC-ND 4.0 license © Authors, 2022.

Evaluation of Immune Nanoparticles for Rapid and Non-Specific Activation of Antiviral and Antibacterial Immune Responses in Cattle, Swine, and Poultry.

Given the rapid potential spread of agricultural pathogens, and the lack of vaccines for many, there is an important unmet need for strategies to induce rapid and non-specific immunity against these viral and bacterial threats. One approach to the problem is to generate non-specific immune responses at mucosal surfaces to rapidly protect from entry and replication of both viral and bacterial pathogens. Using complexes of charged nanoparticle liposomes with both antiviral and antibacterial toll-like receptor (TLR) nucleic acid ligands (termed liposome-TLR complexes or LTC), we have previously demonstrated considerable induction of innate immune responses in nasal and oropharyngeal tissues and protection from viral and bacterial pathogens in mixed challenge studies in rodents, cattle, and companion animals. Therefore, in the present study, we used in vitro assays to evaluate the ability of the LTC immune stimulant to activate key innate immune pathways, particularly interferon pathways, in cattle, swine, and poultry. We found that LTC complexes induced strong production of type I interferons (IFNα and IFNß) in both macrophages and leukocyte cultures from all three species. In addition, the LTC complexes induced the production of additional key protective cytokines (IL-6, IFNγ, and TNFα) in macrophages and leukocytes in cattle and poultry. These findings indicate that the LTC mucosal immunotherapeutic has the capability to activate key innate immune defenses in three major agricultural species and potentially induce broad protective immunity against both viral and bacterial pathogens. Additional animal challenge studies are warranted to evaluate the protective potential of LTC immunotherapy in cattle, swine, and poultry.

SARS-CoV-2 NSP13 interacts with host IRF3, blocking antiviral immune responses.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), poses an unprecedented threat to human health since late 2019. Notably, the progression of the disease is associated with impaired antiviral interferon (IFN) responses. Although multiple viral proteins were identified as potential IFN antagonists, the underlying molecular mechanisms remain to be fully elucidated. In this study, we firstly demonstrate that SARS-CoV-2 NSP13 protein robustly antagonizes IFN response induced by the constitutively active form of transcription factor IRF3 (IRF3/5D). This induction of IFN response by IRF3/5D is independent of the upstream kinase, TBK1, a previously reported NSP13 target, thus indicating that NSP13 can act at the level of IRF3 to antagonize IFN production. Consistently, NSP13 exhibits a specific, TBK1-independent interaction with IRF3, which, moreover, is much stronger than that of NSP13 with TBK1. Furthermore, the NSP13-IRF3 interaction was shown to occur between the NSP13 1B domain and IRF3 IRF association domain (IAD). In agreement with the strong targeting of IRF3 by NSP13, we then found that NSP13 blocks IRF3-directed signal transduction and antiviral gene expression, counteracting IRF3-driven anti-SARS-CoV-2 activity. These data suggest that IRF3 is likely to be a major target of NSP13 in antagonizing antiviral IFN responses and provide new insights into the SARS-CoV-2-host interactions that lead to viral immune evasion.

Defensosomes: a new role for autophagy proteins in innate immune defense.

In recent years, the contribution of exosomes to immunity, inflammation and host-pathogen interaction have been appreciated. Exosomes are small secreted extracellular vesicles from endosomal origin that contain a myriad of cellular molecules (protein, nucleic acids), including surface receptors. We have reported a pathogen-induced and macroautophagy/autophagy-dependent class of exosomes coined as "defensosomes", which protect the host from membrane-targeting toxins. In a recent study, we found that defensosomes decorated with ACE2, the SARS-CoV-2 cellular receptor, are produced in the lungs of patients with COVID-19, and that increased concentration of ACE2-loaded defensosomes is associated with decreased hospitalization length. Mechanistically, SARS-CoV-2 induces the production of ACE2-coated defensosomes, a process requiring the autophagy machinery, which in turn binds and neutralizes the virus. We propose that defensosomes represent a new form of autophagy-mediated innate immunity that contributes to the host's armamentarium against pathogens.

Immune response induced by novel coronavirus infection.

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus (SARS-CoV)-2 has been prominent around the world since it was first discovered, affecting more than 100 million people. Although the symptoms of most infected patients are not serious, there is still a considerable proportion of patients who need hospitalization and even develop fatal symptoms such as cytokine storms, acute respiratory distress syndrome and so on. Cytokine storm is usually described as a collection of clinical manifestations caused by overactivation of the immune system, which plays an important role in tissue injury and multiorgan failure. The immune system of healthy individuals is composed of two interrelated parts, the innate immune system and the adaptive immune system. Innate immunity is the body's first line of defense against viruses; it can quickly perceive viruses through pattern recognition receptors and activate related inflammatory pathways to clear pathogens. The adaptive immune system is activated by specific antigens and is mainly composed of CD4+ T cells, CD8+ T cells and B cells, which play different roles in viral infection. Here, we discuss the immune response after SARS-CoV-2 infection. In-depth study of the recognition of and response of innate immunity and adaptive immunity to SARS-CoV-2 will help to prevent the development of critical cases and aid the exploration of more targeted treatments.

Vitamin D in the prevention or treatment of COVID-19.

This review summarises evidence relating to a potential role for vitamin D supplementation in the prevention or treatment of coronavirus disease 2019 (COVID-19). Laboratory studies show that the active vitamin D metabolite 1,25-dihydroxyvitamin D induces innate antiviral responses and regulates immunopathological inflammation with potentially favourable implications for the host response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Meta-analyses of cross-sectional, case-control and longitudinal studies report consistent protective associations between higher circulating 25-hydroxyvitamin D [25(OH)D] concentrations or vitamin D supplement use and reduced risk and severity of COVID-19. However, Mendelian randomisation studies testing for associations between genetically predicted circulating 25(OH)D concentrations and COVID-19 outcomes have yielded consistently null results. Positive findings from observational epidemiological studies may therefore have arisen as a result of residual or unmeasured confounding or reverse causality. Randomised controlled trials of prophylactic or therapeutic vitamin D supplementation to reduce risk or severity of COVID-19 reporting to date have yielded inconsistent findings. Results of further intervention studies are pending, but current evidence is insufficient to support routine use of vitamin D supplements as a therapeutic or prophylactic agent for COVID-19, or as an adjunct to augment immunogenicity of SARS-CoV-2 vaccination. Accordingly, national and international bodies have not made any recommendations regarding a role for vitamin D in the prevention or treatment of COVID-19.