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Among the current five Variants of Concern, infections caused by SARS-CoV-2 B.1.617.2 (Delta) variant are often associated with the greatest severity. Despite recent advances on the molecular basis of elevated pathogenicity using recombinant proteins, the architecture of intact Delta virions remains veiled. Moreover, pieces of molecular evidence for the detailed mechanism of S-mediated membrane fusion are missing. Here, we showed the pleomorphic nature of Delta virions from electron beam inactivated samples and reported the in situ structure and distribution of S on the authentic Delta variant. We also captured the virus-virus fusion events, which provided pieces of structural evidence for Delta's attenuated dependency on cellular factors for fusion activation, and proposed a model of S-mediated membrane fusion. Besides, site-specific glycan analysis revealed increased oligomannose-type glycosylation of native Delta S than that of the WT S. Together, these results disclose distinctive factors of Delta being the most virulent SARS-CoV-2 variant. [ABSTRACT FROM AUTHOR]

Cancer is now considered a tumor microenvironment (TME) disease, although it was originally thought to be a cell and gene expression disorder. Over the past 20 years, significant advances have been made in understanding the complexity of the TME and its impact on responses to various anticancer therapies, including immunotherapies. Cancer immunotherapy can recognize and kill cancer cells by regulating the body's immune system. It has achieved good therapeutic effects in various solid tumors and hematological malignancies. Recently, blocking of programmed death-1 (PD-1), programmed death-1 ligand-1 (PD-L1), and programmed death Ligand-2 (PD-L2), the construction of antigen chimeric T cells (CAR-T) and tumor vaccines have become popular immunotherapies Tumorigenesis, progression, and metastasis are closely related to TME. Therefore, we review the characteristics of various cells and molecules in the TME, the interaction between PD-1 and TME, and promising cancer immunotherapy therapeutics. [ABSTRACT FROM AUTHOR]

Background: In 2020, a new coronavirus, SARS-CoV-2, quickly spread worldwide within a few months. Although coronaviruses typically infect the upper or lower respiratory tract, the virus RNA can be detected in plasma. The risk of transmitting coronavirus via transfusion of blood products remains. As more asymptomatic infections are identified in COVID-19 cases, blood safety has become particularly important. Methylene blue (MB) photochemical technology has been proven to inactivate lipid-enveloped viruses with high efficiency and safety. The present study aimed to investigate the SARS-CoV-2 inactivation effects of MB in plasma.Methods: The SARS-CoV-2 virus strain was isolated from Zhejiang University. The live virus was harvested from cultured VERO-E6 cells, and mixed with MB in plasma. The MB final concentrations were 0, 1, 2, and 4 μM. The "BX-1 AIDS treatment instrument" was used at room temperature, the illumination adjusted to 55,000 ± 0.5 million Lux, and the plasma was irradiated for 0, 2, 5, 10, 20, and 40 mins using light at a single wavelength of 630 nm. Virus load changes were measured using quantitative reverse transcription- PCR.Results: BX-1 could effectively eliminate SARS-CoV-2 within 2 mins in plasma, and the virus titer declined to 4.5 log10 TCID50 (median tissue culture infectious dose)/mL.Conclusion: BX-1 is based on MB photochemical technology, which was designed to inactivate HIV-1 virus in plasma. It was proven to be safe and reliable in clinical trials of HIV treatment. In this study, we showed that BX-1 could also be applied to inactivate SARS-CoV-2. During the current outbreak, this technique it has great potential for ensuring the safety of blood transfusions, for plasma transfusion therapy in recovering patients, and for preparing inactivated vaccines. [ABSTRACT FROM AUTHOR]

The present study examined the relationship between cytokine and chemokine expression and the clinical presentation of hand, foot and mouth disease (HFMD), which is currently unclear. The present study involved 28 patients with mild HFMD, 44 patients with severe HFMD and 26 healthy children. Venous blood was tested for cytokine [interleukin (IL)-4, IL-12, IL-18, tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ)] and chemokine expression [IL-8, regulated on activation, normal T cell expressed and secreted (RANTES), monocyte chemoattractant protein-1 (MCP-1) and IFN-γ-inducible protein-10 (IP-10)]. Stool samples from the patients were tested for enterovirus 71 (EV71) RNA using reverse transcription-polymerase chain reaction. The results indicated that all cytokine/chemokine levels were increased in patients with severe HFMD compared with in patients with mild HFMD or control subjects. In addition, RANTES, MCP-1, IL-4, IL-12 and IL-18 levels were higher in mild HFMD patients than in the controls. In patients with severe HFMD, all expression levels (with the exception of IL-8 and IL-4) were increased in patients with encephalitis plus pulmonary edema compared with those with encephalitis alone. Furthermore, all levels (with the exception of IL-8) were increased in EV71-positive patients compared with EV71-negative patients. In mild HFMD, all levels (with the exception of IL-8 and IL-4) were increased in EV71-positive patients compared with EV71-negative patients. However, in severe HFMD, only RANTES, IP-10 and IFN-γ levels were increased in EV71-positive patients compared with EV71-negative patients. In the EV71-negative group, all levels were increased in severe HFMD compared with mild HFMD. In the EV71-positive group, all levels (with the exception of IL-8) were increased in severe HFMD compared with mild HFMD. These results indicated that cytokines and chemokines participate in HFMD pathogenesis, and may be useful to monitor disease progression and predict prognosis. [ABSTRACT FROM AUTHOR]

Macrophages are major targets of human immunodeficiency virus (HIV) and can act as long-term reservoirs of the virus. Chronic HIV-1 infection is associated with dysregulated inflammation. Recepteur d'origine nantais (RON) is expressed in tissue resident macrophages and functions to maintain inflammatory homeostasis. The present study aimed to compare the expression of RON on HIV-positive and - negative participants, and to investigate the mechanism by which HIV-1 influences the expression and function of RON in the JLTRG T cell line. The levels of RON and the RON ligand, macrophage-stimulating protein (MSP), in the peripheral blood of HIV-1-positive patients that were receiving (n=22) or not receiving highly active anti-retroviral therapy (HAART) (n=82) and 37 healthy control participants were determined by enzyme-linked immunosorbent assay. Expression of RON and MSP in the JLTRG T cell line was assessed by western blotting and the subcellular location was analyzed by fluorescence microscopy. JLTRG cells were co-cultured with a cell line that stably expresses HIV, H9/HTLV-IIIB, and alterations in the levels of RON and nuclear factor-κB (NF-κB) in JLTRG cells were assessed by western blotting. The expression of RON and MSP were significantly different in the serum of HIV-1- positive patients that were receiving HAART compared with those not receiving H AART (P<0.05) a nd healthy control patients (P<0.01). RON was detected in JLTRG cells, and was shown to be downregulated by HIV-1 infection. HIV-1 infection of JLTRG cells also reduced NF-κB phosphorylation. Thus, HIV-1 was shown to downregulate the expression and phosphorylation of RON by targeting the NF-κB pathway. [ABSTRACT FROM AUTHOR]

Intracellular proton extrusion in gastric cancer cells has been reported to promote cancer cell survival under acidic conditions via hydrogen/potassium adenosine triphosphatase (H+/K+-ATPase). Rabeprazole is a frequently used second-generation proton pump inhibitor (PPI) that irreversibly inactivates gastric H+/K+-ATPase. Therefore, we hypothesized that rabeprazole could reduce the viability of gastric cancer cells. In the present study, four human gastric cancer cell lines and one non-cancer gastric cell line were cultured. Cell viability, the α- and β-subunits of H+/K+-ATPase and cellular apoptosis were analyzed by dye exclusion assay, reverse transcription-polymerase chain reaction and annexin V-fluorescein isothiocyanate/propidium iodide staining, respectively. The expression level of total extracellular signal-regulated protein kinase 1/2 (ERK 1/2) and phosphorylated-ERK protein was detected by western blot analysis. Gastric cancer cell lines were more tolerant of the acidic culture media than non-cancer cells. Administration of rabeprazole led to a marked decrease in the viability of MKN-28 cells. Exposure to rabeprazole induced significant apoptosis in AGS cells. Rabeprazole completely inhibited the phosphorylation of ERK 1/2 in the MKN-28 cells, whereas the same effect was not observed in either the KATO III or MKN-45 cells. The ERK 1/2 inhibitor, PD98059, attenuated the viability of the AGS cells. A similar antiproliferative effect was observed in the rabeprazole treatment group. In addition, PD98059 and rabeprazole were able to efficaciously inhibit the phosphorylation of ERK 1/2 in the gastric cancer cells. Therefore, it was concluded that rabeprazole can attenuate the cell viability of human gastric cancer cells through inactivation of the ERK1/2 signaling pathway. The results of the present study demonstrate that rabeprazole inhibits the viability of gastric cancer cells in vitro and may serve as a novel antineoplastic agent. [ABSTRACT FROM AUTHOR]

Domestic ducks are natural reservoirs of avian influenza viruses and serve as reassortant hosts for new virus subtypes. We isolated 2 novel influenza A(H5N8) viruses from domestic ducks in eastern China, sequenced their genomes, and tested their pathogenicity in chickens and mice. Circulation of these viruses may pose health risks for humans. [ABSTRACT FROM AUTHOR]

We assessed a colloidal gold immunochromatographic assay (GICA) for rapid detection of influenza A (H7N9) and compared it with reverse-transcription-polymerase chain reaction (RT-PCR) and viral culture. Samples from 35 H7N9 infected patients were collected, including 45 throat swab samples, 56 sputum samples, and 39 feces samples. All samples were tested by GICA, viral culture, and RT-PCR. GICA specifically reacted with recombinant HA proteins, virus lysates, and clinical samples fromH7 subtype viruses. Compared with RT-PCR, GICA demonstrated low sensitivity (33.33%) but high specificity (97.56%). The positive rate of GICA tests for samples collected in the period from 8 to 21 days after contact with poultry was much higher than those for samples collected before or after this period. Compared with viral culture, GICA showed sensitivity of 91.67% and specificity of 82.03%. Sputum specimens weremore likely to test positive for H7N9 virus than samples from throat swabs and feces. The GICA-based H7 test is a reliable, rapid, and convenient method for the screening and diagnosis of influenza A (H7N9) disease, especially for the sputum specimens with high viral load. It may be helpful in managing H7N9 epidemics and preliminary diagnosis in early stages in resource-limited settings. [ABSTRACT FROM AUTHOR]

Summary Background Human infection with avian influenza A H7N9 virus emerged in eastern China in February, 2013, and has been associated with exposure to poultry. We report the clinical and microbiological features of patients infected with influenza A H7N9 virus and compare genomic features of the human virus with those of the virus in market poultry in Zhejiang, China. Methods Between March 7 and April 8, 2013, we included hospital inpatients if they had new-onset respiratory symptoms, unexplained radiographic infiltrate, and laboratory-confirmed H7N9 virus infection. We recorded histories and results of haematological, biochemical, radiological, and microbiological investigations. We took throat and sputum samples, used RT-PCR to detect M, H7, and N9 genes, and cultured samples in Madin-Darby canine kidney cells. We tested for co-infections and monitored serum concentrations of six cytokines and chemokines.We collected doacal swabs from 86 birds from epidemiologically linked wet markets and inoculated embryonated chicken eggs with the samples. We identified and subtyped isolates by RT-PCR sequencing. RNA extraction, complementary DNA synthesis, and PCR sequencing were done for one human and one chicken isolate. We characterised and phylogenetically analysed the eight gene segments of the viruses in the patient's and the chicken's isolates, and constructed phylogenetic trees of H, N, PB2, and NS genes. Findings We identified four patients (mean age 56 years), all of whom had contact with poultry 3-8 days before disease onset. They presented with fever and rapidly progressive pneumonia that did not respond to antibiotics. Patients were leucopenic and lymphopenic, and had impaired liver or renal function, substantially increased serum cytokine or chemokine concentrations, and disseminated intravascular coagulation with disease progression. Two patients died. Sputum specimens were more likely to test positive for the H7N9 virus than were samples from throat swabs. The viral isolate from the patient was closely similar to that from an epidemiologically linked market chicken. All viral gene segments were of avian origin. The H7 of the isolated viruses was closest to that of the H7N3 virus from domestic ducks in Zhejiang, whereas the N9 was closest to that of the wild bird H7N9 virus in South Korea. We noted Gln226Leu and Gly186Val substitutions in human virus H7 (associated with increased affinity for cx-2,6-1inked sialic acid receptors) and the PB2 Asp701Asn mutation (associated with mammalian adaptation). Ser31Asn mutation, which is associated with adamantane resistance, was noted in viral M2. Interpretation Cross species poultry-to-person transmission of this new reassortant H7N9 virus is associated with severe pneumonia and multiorgan dysfunction in human beings. Monitoring of the viral evolution and further study of disease pathogenesis will improve disease management, epidemic control, and pandemic preparedness. Fundin9 Larry Chi-Kin Yung, National Key Program for Infectious Diseases of China. [ABSTRACT FROM AUTHOR]