Antiviral Immune Responses to Invertebrate Iridescent Virus 6 in Drosophila

The innate immune system is a critical first line of defense against invading pathogens. Innate immunity directly detects pathogens, sets up an appropriate adaptive response, and can directly kill pathogens. Drosophila may lack an adaptive immune response, but have a robust innate immune system with a variety of defense effector mechanisms. While the responses to bacteria, fungi, and RNA viruses have been well characterized, not much is known about the response to DNA viruses. My studies have set out to characterize the Drosophila immune response to a DNA virus, utilizing the large dsDNA virus, Invertebrate Iridescent Virus 6 (IIV-6). IIV-6 infection causes shortened lifespan, and in later stages of infection, flies present with abdominal swelling and iridescent blue color. Our objectives were to identify pathways flies use to protect themselves from IIV-6 infection, determine how this protection is mediated, and to identify any immune inhibitors that IIV-6 uses to suppress innate immune signaling. I have found that IIV-6 strongly up-regulates a class of stress proteins with unknown function, termed Turandots, after infection in vivo or in vitro. This induction is dependent upon viral replication, requires JAK-STAT activation, and activation of p38b MAPK. In addition, the unpaireds, which function as JAK-STAT ligands, are upregulated after IIV-6 infection in a p38b-dependent manner. Together, this data suggests that p38b activation leads to production of unpaired cytokines and activation of JAK-STAT signaling to induce Turandots. I have also found that IIV-6 infected cells secrete protective factors. This response is induced within 12 hours of IIV-6 infection, exosome-mediated, and provides robust protection to naive cells challenged with an mCherry-expressing strain of IIV-6. Additionally, IIV-6 inhibits two major immune responses in Drosophila, the IMD and Toll pathways. Stimulation of IIV-6 infected Drosophila S2* cells with either IMD or Toll stimulators results in very poor antimicrobial peptide responses. Yet, IMD and Relish are still cleaved upon stimulation in IIV-6 infected cells, indicating that the block is downstream. In support of this finding, IIV-6 infected flies respond very poorly to infection with the enterobacteria Erwinia carotovora carotovora compared to mock-injected flies

p38b and JAK-STAT signaling protect against Invertebrate iridescent virus 6 infection in Drosophila

The fruit fly Drosophila melanogaster is a powerful model system for the study of innate immunity in vector insects as well as mammals. For vector insects, it is particularly important to understand all aspects of their antiviral immune defenses, which could eventually be harnessed to control the transmission of human pathogenic viruses. The immune responses controlling RNA viruses in insects have been extensively studied, but the response to DNA virus infections is poorly characterized. Here, we report that infection of Drosophila with the DNA virus Invertebrate iridescent Virus 6 (IIV-6) triggers JAK-STAT signaling and the robust expression of the Turandots, a gene family encoding small secreted proteins. To drive JAK-STAT signaling, IIV-6 infection more immediately induced expression of the unpaireds, a family of IL-6-related cytokine genes, via a pathway that required one of the three Drosophila p38 homologs, p38b. In fact, both Stat92E and p38b were required for the survival of IIV-6 infected flies. In addition, in vitro induction of the unpaireds required an NADPH-oxidase, and in vivo studies demonstrated Nox was required for induction of TotA. These results argue that ROS production, triggered by IIV-6 infection, leads to p38b activation and unpaired expression, and subsequent JAK-STAT signaling, which ultimately protects the fly from IIV-6 infection

IIV-6 Inhibits NF-kappaB Responses in Drosophila

The host immune response and virus-encoded immune evasion proteins pose constant, mutual selective pressure on each other. Virally encoded immune evasion proteins also indicate which host pathways must be inhibited to allow for viral replication. Here, we show that IIV-6 is capable of inhibiting the two Drosophila NF-kappaB signaling pathways, Imd and Toll. Antimicrobial peptide (AMP) gene induction downstream of either pathway is suppressed when cells infected with IIV-6 are also stimulated with Toll or Imd ligands. We find that cleavage of both Imd and Relish, as well as Relish nuclear translocation, three key points in Imd signal transduction, occur in IIV-6 infected cells, indicating that the mechanism of viral inhibition is farther downstream, at the level of Relish promoter binding or transcriptional activation. Additionally, flies co-infected with both IIV-6 and the Gram-negative bacterium, Erwinia carotovora carotovora, succumb to infection more rapidly than flies singly infected with either the virus or the bacterium. These findings demonstrate how pre-existing infections can have a dramatic and negative effect on secondary infections, and establish a Drosophila model to study confection susceptibility

IIV-6 Inhibits NF-κB Responses in Drosophila.

The host immune response and virus-encoded immune evasion proteins pose constant, mutual selective pressure on each other. Virally encoded immune evasion proteins also indicate which host pathways must be inhibited to allow for viral replication. Here, we show that IIV-6 is capable of inhibiting the two Drosophila NF-κB signaling pathways, Imd and Toll. Antimicrobial peptide (AMP) gene induction downstream of either pathway is suppressed when cells infected with IIV-6 are also stimulated with Toll or Imd ligands. We find that cleavage of both Imd and Relish, as well as Relish nuclear translocation, three key points in Imd signal transduction, occur in IIV-6 infected cells, indicating that the mechanism of viral inhibition is farther downstream, at the level of Relish promoter binding or transcriptional activation. Additionally, flies co-infected with both IIV-6 and the Gram-negative bacterium, Erwinia carotovora carotovora, succumb to infection more rapidly than flies singly infected with either the virus or the bacterium. These findings demonstrate how pre-existing infections can have a dramatic and negative effect on secondary infections, and establish a Drosophila model to study confection susceptibility

Results of the Sukuma Ndoda (“Stand up, Man”) HIV Self-Screening and Assisted Linkage to Care Project in Johannesburg: A Quasi-Experimental Pre–Post Evaluation

BackgroundHIV testing rates among South African men lag behind rates for women and national targets. Community-based HIV self-screening (HIVSS) distribution and follow-up by community health workers (CHWs) is a scalable option to increase testing coverage, diagnosis, and treatment initiation. We provided HIVSS and assisted linkage to care to men not recently tested (within the past 12 months) residing in high-HIV-burden areas of Johannesburg.MethodsCHWs distributed HIVSS in 6 clinic catchment areas. Follow-up to encourage confirmatory testing and antiretroviral therapy initiation was conducted through personal support (PS) or an automated short message service (SMS) follow-up and linkage system in 3 clinic areas each. Using a quasi-experimental pre-post design, we compared differences in the proportion of men testing in the clinic catchment areas during the HIVSS campaign (June-August 2019) to the 3 months prior (March-May 2019) and compared treatment initiations by assisted linkage strategy.ResultsAmong 4793 participants accepting HIVSS, 62% had never tested. Among 3993 participants with follow-up data, 90.6% reported using their HIVSS kit. Testing coverage among men increased by 156%, from under 4% when only clinic-based HIV testing services were available to 9.5% when HIVSS and HIV testing services were available (z = -11.6; P < 0.01). Reported test use was higher for men followed through PS (99% vs. 68% in SMS); however, significantly more men reported reactive self-test results in the SMS group compared with PS (6.4% vs. 2.0%), resulting in more antiretroviral therapy initiations in the SMS group compared with PS (23 vs. 9; P < 0.01).ConclusionsCHW HIVSS distribution significantly increases testing among men. While PS enabled personalized follow-up, reporting differences indicate SMS is more acceptable and better aligned with expectations of privacy associated with HIVSS

A single vertebrate DNA virus protein disarms invertebrate immunity to RNA virus infection

Virus-host interactions drive a remarkable diversity of immune responses and countermeasures. We found that two RNA viruses with broad host ranges, vesicular stomatitis virus (VSV) and Sindbis virus (SINV), are completely restricted in their replication after entry into Lepidopteran cells. This restriction is overcome when cells are co-infected with vaccinia virus (VACV), a vertebrate DNA virus. Using RNAi screening, we show that Lepidopteran RNAi, Nuclear Factor-kappaB, and ubiquitin-proteasome pathways restrict RNA virus infection. Surprisingly, a highly conserved, uncharacterized VACV protein, A51R, can partially overcome this virus restriction. We show that A51R is also critical for VACV replication in vertebrate cells and for pathogenesis in mice. Interestingly, A51R colocalizes with, and stabilizes, host microtubules and also associates with ubiquitin. We show that A51R promotes viral protein stability, possibly by preventing ubiquitin-dependent targeting of viral proteins for destruction. Importantly, our studies reveal exciting new opportunities to study virus-host interactions in experimentally-tractable Lepidopteran systems

Antibody predictors of mortality and lung function trends in myositis spectrum interstitial lung disease

Objectives: The impact of autoantibody profiles on the prognosis for idiopathic inflammatory myositis-associated interstitial lung disease (IIM-ILD) and myositis spectrum ILD with myositis-specific antibodies (MSAs) remains unclear. This retrospective cohort study examined whether serological profiles were associated with mortality or longitudinal lung function change. Methods: The baseline clinical/demographic characteristics and follow-up lung function data of consecutive adult patients with IIM-ILD or interstitial pneumonia with autoimmune features (IPAF) positive for MSAs (IPAF-MSA) were extracted from three hospitals. Univariate and multivariate Cox proportional hazards analyses were used to compare mortality between groups of patients with different autoantibodies. Regression models were used to analyse their lung function trends. Results: Of the 430 included patients, 81% met the IIM criteria, and the remaining 19% were diagnosed with IPAF-MSA. On univariate analysis, the risk factors associated with mortality included higher age, Charlson Comorbidity Index, and CRP; and lower BMI, baseline TLCO% and FEV1%. Compared with anti-MDA5 negativity, anti-MDA5 positivity (MDA5+) was associated with higher mortality in the first 3 months [hazard ratio (HR) 65.2, 95% CI 14.1, 302.0], while no significant difference was seen thereafter (HR 0.55, 95% CI 0.14, 2.28). On multivariate analysis, combined anti-synthetase antibodies were associated with a reduced risk of mortality (HR 0.63), although individually, mortality was reduced in patients with anti-Jo1+ (HR 0.61, 95% CI 0.4-0.87) and increased in patients with anti-PL7+ (HR 2.07, 95% CI 1.44-2.99). Anti-MDA5+ was associated with slow improvement in %FVC over the first 3 years, while anti-PL7+ was linked with a slow decline from 12 months onwards. Conclusion: Among the autoantibody profiles in myositis spectrum disorders, anti-MDA5+ and anti-PL7+ conferred higher mortality risks in patients with IIM-ILD. Survivors of an early peak of mortality in anti-MDA5+ disease appeared to have a favourable prognosis.Funding: No specific funding was received from any bodies in the public, commercial or not-for-profit sectors to carry out the work described in this article. Disclosure statement: J.H.: none declared, A.L.: none declared, J.M.: none declared, M.N.: none declared, S.S.A.: none declared, C.S.: none declared, C.O.: none declared, A.D.: consultant of: Boehringer Ingelhime, Brainomix, L.P.: none declared, S.A.: none declared, B.A.-M.: none declared, M.A.G.-G.: none declared, A.P.: none declared, A.W.: none declared, K.T.: none declared, H.R.: none declared, F.C.: none declared, V.K.: none declared, B.L.: none declared, A.V.W.: speakers bureau from Boehringer Ingelheim, Roche, and Veracyte, and consultant for: Boehringer Ingelheim, Roche, and Veracyte, S.N.: none declared, J.G.: none declared, E.A.R.: none declared, P.A.G.: speakers bureau from UCB, consultant for Eli Lilly, and Galapagos, and grant/research support from Corbus Pharmaceuticals. Acknowledgements: This work has previously been presented in abstract form at EULAR 2023. J.H. received personal support through grants from the King’s College Hospital Charity

Study of the reaction e^{+}e^{-} -->J/psi\pi^{+}\pi^{-} via initial-state radiation at BaBar

We study the process $e^+e^-\to J/\psi\pi^{+}\pi^{-}$ with initial-state-radiation events produced at the PEP-II asymmetric-energy collider. The data were recorded with the BaBar detector at center-of-mass energies 10.58 and 10.54 GeV, and correspond to an integrated luminosity of 454 $\mathrm{fb^{-1}}$. We investigate the $J/\psi \pi^{+}\pi^{-}$ mass distribution in the region from 3.5 to 5.5 $\mathrm{GeV/c^{2}}$. Below 3.7 $\mathrm{GeV/c^{2}}$ the $\psi(2S)$ signal dominates, and above 4 $\mathrm{GeV/c^{2}}$ there is a significant peak due to the Y(4260). A fit to the data in the range 3.74 -- 5.50 $\mathrm{GeV/c^{2}}$ yields a mass value $4244 \pm 5$ (stat) $\pm 4$ (syst)$\mathrm{MeV/c^{2}}$ and a width value $114 ^{+16}_{-15}$ (stat)$\pm 7$(syst)$\mathrm{MeV}$ for this state. We do not confirm the report from the Belle collaboration of a broad structure at 4.01 $\mathrm{GeV/c^{2}}$. In addition, we investigate the $\pi^{+}\pi^{-}$ system which results from Y(4260) decay

Measurement of event shapes in deep inelastic scattering at HERA

Inclusive event-shape variables have been measured in the current region of the Breit frame for neutral current deep inelastic ep scattering using an integrated luminosity of 45.0 pb^-1 collected with the ZEUS detector at HERA. The variables studied included thrust, jet broadening and invariant jet mass. The kinematic range covered was 10 < Q^2 < 20,480 GeV^2 and 6.10^-4 < x < 0.6, where Q^2 is the virtuality of the exchanged boson and x is the Bjorken variable. The Q dependence of the shape variables has been used in conjunction with NLO perturbative calculations and the Dokshitzer-Webber non-perturbative corrections (`power corrections') to investigate the validity of this approach.Comment: 7+25 pages, 6 figure