Optimization of Naked DNA Delivery for Interferon Subtype Immunotherapy in Cytomegalovirus Infection

Type I interferon (IFN) gene therapy modulates the immune response leading to inflammatory heart disease following cytomegalovirus (CMV) infection in a murine model of post-viral myocarditis. Efficacy of different immunisation protocols for the IFN constructs was influenced by the dose of DNA, subtype choice, combination use, pre-medication, and timing of DNA administration. Optimal efficacy was found with bupivacaine treatment prior to DNA inoculation of 200mg IFN DNA 14 days prior to virus challenge. Maximal antiviral and antimyocarditic effects were achieved with this vaccination schedule. Furthermore, inoculation of synergistic IFN subtypes demonstrated enhanced efficacy when delivered either alone or with CMV gB DNA vaccination in the CMV model. Thus naked DNA delivery of IFN provides an avenue of immunotherapy for regulating herpesvirus-induced diseases

Leishmania infantum Asparagine Synthetase A Is Dispensable for Parasites Survival and Infectivity

A growing interest in asparagine (Asn) metabolism has currently been observed in cancer and infection fields. Asparagine synthetase (AS) is responsible for the conversion of aspartate into Asn in an ATP-dependent manner, using ammonia or glutamine as a nitrogen source. There are two structurally distinct AS: the strictly ammonia dependent, type A, and the type B, which preferably uses glutamine. Absent in humans and present in trypanosomatids, AS-A was worthy of exploring as a potential drug target candidate. Appealingly, it was reported that AS-A was essential in Leishmania donovani, making it a promising drug target. In the work herein we demonstrate that Leishmania infantum AS-A, similarly to Trypanosoma spp. and L. donovani, is able to use both ammonia and glutamine as nitrogen donors. Moreover, we have successfully generated LiASA null mutants by targeted gene replacement in L. infantum, and these parasites do not display any significant growth or infectivity defect. Indeed, a severe impairment of in vitro growth was only observed when null mutants were cultured in asparagine limiting conditions. Altogether our results demonstrate that despite being important under asparagine limitation, LiAS-A is not essential for parasite survival, growth or infectivity in normal in vitro and in vivo conditions. Therefore we exclude AS-A as a suitable drug target against L. infantum parasites

Improved vaccine protection against retrovirus infection after co-administration of adenoviral vectors encoding viral antigens and type I interferon subtypes

Background Type I interferons (IFNs) exhibit direct antiviral effects, but also distinct immunomodulatory properties. In this study, we analyzed type I IFN subtypes for their effect on prophylactic adenovirus-based anti-retroviral vaccination of mice against Friend retrovirus (FV) or HIV. Results Mice were vaccinated with adenoviral vectors encoding FV Env and Gag proteins alone or in combination with vectors encoding IFNα1, IFNα2, IFNα4, IFNα5, IFNα6, IFNα9 or IFNβ. Only the co-administration of adenoviral vectors encoding IFNα2, IFNα4, IFNα6 and IFNα9 resulted in strongly improved immune protection of vaccinated mice from subsequent FV challenge infection with high control over FV-induced splenomegaly and reduced viral loads. The level of protection correlated with augmented virus-specific CD4+ T cell responses and enhanced antibody titers. Similar results were obtained when mice were vaccinated against HIV with adenoviral vectors encoding HIV Env and Gag-Pol in combination with various type I IFN encoding vectors. Here mainly CD4+ T cell responses were enhanced by IFNα subtypes. Conclusions Our results indicate that certain IFNα subtypes have the potential to improve the protective effect of adenovirus-based vaccines against retroviruses. This correlated with augmented virus-specific CD4+ T cell and antibody responses. Thus, co-expression of select type I IFNs may be a valuable tool for the development of anti-retroviral vaccines

Persistent and compartmentalised disruption of dendritic cell subpopulations in the lung following influenza A virus infection

Immunological homeostasis in the respiratory tract is thought to require balanced interactions between networks of dendritic cell (DC) subsets in lung microenvironments in order to regulate tolerance or immunity to inhaled antigens and pathogens. Influenza A virus (IAV) poses a serious threat of long-term disruption to this balance through its potent pro-inflammatory activities. In this study, we have used a BALB/c mouse model of A/PR8/34 H1N1 Influenza Type A Virus infection to examine the effects of IAV on respiratory tissue DC subsets during the recovery phase following clearance of the virus. In adult mice, we found differences in the kinetics and activation states of DC residing in the airway mucosa (AMDC) compared to those in the parenchymal lung (PLDC) compartments. A significant depletion in the percentage of AMDC was observed at day 4 post-infection that was associated with a change in steady-state CD11b+ and CD11b- AMDC subset frequencies and significantly elevated CD40 and CD80 expression and that returned to baseline by day 14 post-infection. In contrast, percentages and total numbers of PLDC were significantly elevated at day 14 and remained so until day 21 postinfection. Accompanying this was a change in CD11b+and CD11b- PLDC subset frequencies and significant increase in CD40 and CD80 expression at these time points. Furthermore, mice infected with IAV at 4 weeks of age showed a significant increase in total numbers of PLDC, and increased CD40 expression on both AMDC and PLDC, when analysed as adults 35 days later. These data suggest that the rate of recovery of DC populations following IAV infection differs in the mucosal and parenchymal compartments of the lung and that DC populations can remain disrupted and activated for a prolonged period following viral clearance, into adulthood if infection occurred early in life