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Cyclic GMP-AMP synthase (cGAS) detects cytosolic DNA during virus infection and induces an antiviral state. cGAS signals by synthesis of a second messenger, cyclic GMP-AMP (cGAMP), which activates stimulator of interferon genes (STING). We show that cGAMP is incorporated into viral particles, including lentivirus and herpesvirus virions, when these are produced in cGAS-expressing cells. Virions transferred cGAMP to newly infected cells and triggered a STING-dependent antiviral program.These effects were independent of exosomes and viral nucleic acids. Our results reveal a way by which a signal for innate immunity is transferred between cells, potentially accelerating and broadening antiviral responses. Moreover, infection of dendritic cells with cGAMP-loaded lentiviruses enhanced their activation. Loading viral vectors with cGAMP therefore holds promise for vaccine development.

Background Optimising periprocedural management of direct oral anticoagulation in patients with atrial fibrillation on chronic treatment undergoing major surgeries is an important aspect of balancing the risk of surgery-related bleeding with the risk of thromboembolic events, which may vary by surgery type. Methods This subanalysis of the prospective EMIT-AF/VTE programme assessed periprocedural-edoxaban management, according to physicians’ decisions, and bleeding and thromboembolic event rates in patients who underwent major vs. nonmajor surgeries. Edoxaban interruption and clinical outcomes were compared between major vs. nonmajor surgeries and between renal function subgroups (creatinine clearance [CrCL] ≤ 50 mL/min vs. > 50 mL/min). Results We included 276 major and 512 nonmajor surgeries. The median pre- and postprocedural duration of edoxaban interruption in major vs. nonmajor surgeries was 4 vs. 1 days, whereas median duration of interruption for those with preprocedural-only and postprocedural-only interruption was 2 vs. 1 days and 2 vs. 0 days, respectively ( P  < 0.0001). Rates of all bleeding and clinically relevant nonmajor bleeding were numerically higher in major vs. nonmajor surgeries. Event rates (number of events per 100 surgeries) were low overall (< 6 events per 100 surgeries), independent of renal function subgroups. Conclusion In this subanalysis of the EMIT-AF/VTE programme, periprocedural-edoxaban interruption was significantly longer in patients undergoing major vs. nonmajor surgery. This clinician-driven approach was associated with low rates of bleeding and thromboembolic events following both major and nonmajor surgeries. Trial registration NCT02950168, registered October 31, 2016; NCT02951039, registered November 1, 2016.

Non-recommended dosing occurs in ~25–50% of non-vitamin K antagonist oral anticoagulant prescriptions, with limited data for edoxaban. We analyzed edoxaban dosing patterns in atrial fibrillation patients from the Global ETNA-AF program, relating patterns to baseline characteristics and 1-year clinical outcomes. The following dosing groups were compared: non-recommended 60 mg (“overdosed”) vs. recommended 30 mg; non-recommended 30 mg (“underdosed”) vs. recommended 60 mg. Most (22,166/26,823; 82.6%) patients received recommended doses. Non-recommended dosing was more frequent near label-specified dose-reduction thresholds. Ischemic stroke (IS; HR 0.85, 95% CI 0.50–1.47; p = 0.6) and major bleeding (MB; HR 1.47, 95% CI 0.97–2.71; p = 0.07) did not differ between recommended 60 mg and “underdosed” groups, whereas all-cause (HR 1.61, 95% CI 1.23–2.08; p = 0.0003) and cardiovascular deaths (HR 1.61, 95% CI 1.11–2.38; p = 0.01) were higher in the “underdosed” group. Compared with recommended 30 mg, the “overdosed” group had lower IS (HR 0.51, 95% CI 0.28–0.98; p = 0.04) and all-cause death (HR 0.74, 95% CI 0.55–0.98; p = 0.03) without higher MB (HR 0.74, 95% CI 0.46–1.22; p = 0.2). In conclusion: non-recommended dosing was infrequent, but more common near dose-reduction thresholds. “Underdosing” was not associated with better clinical outcomes. The “overdosed” group had lower IS and all-cause death without higher MB.

Type I interferons (IFN-I) are important cytokines linking innate and adaptive immunity 1 . Plasmacytoid dendritic cells make high levels of IFN-I in response to viral infection and are thought to be the major source of the cytokines in vivo 2 . Here, we show that conventional non-plasmacytoid dendritic cells taken from mice infected with a dendritic-cell-tropic strain of lymphocytic choriomeningitis virus make similarly high levels of IFN-I on subsequent culture. Similarly, non-plasmacytoid dendritic cells secrete high levels of IFN-I in response to double-stranded RNA (dsRNA), a major viral signature 3 , when the latter is introduced into the cytoplasm to mimic direct viral infection. This response is partially dependent on the cytosolic dsRNA-binding enzyme protein kinase R 4 and does not require signalling through toll-like receptor (TLR) 3, a surface receptor for dsRNA 5 . Furthermore, we show that sequestration of dsRNA by viral NS1 (refs 6 , 7 ) explains the inability of conventional dendritic cells to produce IFN-I on infection with influenza. Our results suggest that multiple dendritic cell types, not just plasmacytoid cells, can act as specialized interferon-producing cells in certain viral infections, and reveal the existence of a TLR-independent pathway for dendritic cell activation that can be the target of viral interference.

Prevention of HIV-1 transmission at mucosal surfaces will likely require durable pre-existing mucosal anti-HIV-1 antibodies (Abs). Defining the ontogeny, specificities and potentially protective nature of the initial mucosal virus-specific B-cell response will be critical for understanding how to induce protective Ab responses by vaccination. Genital fluids from patients within the earliest stages of acute HIV-1 infection (Fiebig I–VI) were examined for multiple anti-HIV specificities. Gp41 (but not gp120) Env immunoglobulin (Ig)A Abs were frequently elicited in both plasma and mucosal fluids within the first weeks of transmission. However, shortly after induction, these initial mucosal gp41 Env IgA Abs rapidly declined with a t1/2 of ∼2.7 days. B-cell-activating factor belonging to the TNF family (BAFF) was elevated immediately preceding the appearance of gp41 Abs, likely contributing to an initial T-independent Ab response. HIV-1 transmission frequently elicits mucosal HIV-1 envelope-specific IgA responses targeted to gp41 that have a short half-life.

Hepatitis B virus (HBV) infection is thought to be controlled by virus-specific cytotoxic T lymphocytes (CTL). We have recently shown that HBV-specific CTL can abolish HBV replication noncytopathically in the liver of transgenic mice by secreting tumor necrosis factor α (TNF-α ) and interferon γ (IFN-γ ) after antigen recognition. We now demonstrate that hepatocellular HBV replication is also abolished noncytopathically during lymphocytic choriomeningitis virus (LCMV) infection, and we show that this process is mediated by TNF-α and IFN-α /β produced by LCMV-infected hepatic macrophages. These results confirm the ability of these inflammatory cytokines to abolish HBV replication; they elucidate the mechanism likely to be responsible for clearance of HBV in chronically infected patients who become superinfected by other hepatotropic viruses; they suggest that pharmacological activation of intrahepatic macrophages may have therapeutic value in chronic HBV infection; and they raise the possibility that conceptually similar events may be operative in other viral infections as well.

Doc number: P183