Immune Evasion by Herpes Simplex Viruses

Infection with herpes simplex viruses type 1 (HSV-1) and type 2 (HSV-2) is extremely frequent in the human population, as well as recurrent reactivations due to lifelong infection. Infection and persistence of HSVs within healthy individuals likely results as a consequence of numerous molecular determinants evolved by these pathogens to escape both immediate and long-term host antiviral mechanisms. Indeed, HSVs harbor an arsenal of proteins that confer them stealth by negatively modulating immune function. Consequently, these viruses perpetuate within the host, altogether silently shedding onto other individuals. In this chapter, we discuss HSV determinants that interfere with cellular antiviral factors, as well as viral determinants that hamper innate and adaptive immune components intended to control such microbes. The identification of HSV evasion molecules that modulate the immune system, as well as the understanding of their mechanisms of action, should facilitate the design of novel prophylactic and therapeutic strategies to overcome infection and disease elicited by these viruses. This chapter is intended to provide an overview of the evasion mechanisms evolved by herpes simplex viruses to escape numerous host antiviral mediators

Experimental Dissection of the Lytic Replication Cycles of Herpes Simplex Viruses in vitro

Herpes simplex viruses type 1 and type 2 (HSV-1 and HSV-2) produce lifelong infections and are highly prevalent in the human population. Both viruses elicit numerous clinical manifestations and produce mild-to-severe diseases that affect the skin, eyes, and brain, among others. Despite the existence of numerous antivirals against HSV, such as acyclovir and acyclovir-related analogs, virus variants that are resistant to these compounds can be isolated from immunosuppressed individuals. For such isolates, second-line drugs can be used, yet they frequently produce adverse side effects. Furthermore, topical antivirals for treating cutaneous HSV infections usually display poor to moderate efficacy. Hence, better or novel anti-HSV antivirals are needed and details on their mechanisms of action would be insightful for improving their efficacy and identifying specific molecular targets. Here, we review and dissect the lytic replication cycles of herpes simplex viruses, discussing key steps involved in cell infection and the processes that yield new virions. Additionally, we review and discuss rapid, easy-to-perform and simple experimental approaches for studying key steps involved in HSV replication to facilitate the identification of the mechanisms of action of anti-HSV compounds

Procesamiento de consultas métrico-temporales

Las bases de datos actuales permiten almacenar datos no estructurados tales como imágenes, sonido, video, datos geométricos, etc. Las tecnologías tradicionales de bases de datos no son aplicables en este ámbito. El modelo de bases de datos métrico-temporal permite abordar aquellas situaciones en las que resulta necesario realizar búsquedas por similitud sobre datos no estructurados pero teniendo en cuenta también la componente temporal. En este modelo se combinan los espacios métricos con las bases de datos temporales, permitiendo así procesar consultas por similitud restringidas a un intervalo o a un instante de tiempo. Nuestra área de investigación es el diseño de índices eficientes para este tipo de bases de datos.Eje: Bases de datos y minería de datosRed de Universidades con Carreras en Informática (RedUNCI

Procesamiento de consultas y aplicaciones del modelo métrico temporal

Las bases de datos actuales permiten almacenar datos no estructurados tales como imágenes, sonido, video, datos geométricos, etc. Las tecnologías tradicionales de bases de datos no son aplicables en este ámbito. Nuevos modelos de bases de datos surgen para cubrir las necesidades de almacenamiento y búsqueda en estas bases de datos. Entre estos nuevos modelos podemos nombrar el espacial, el temporal, el de espacios métricos y el métricotemporal, entre otros. Nuestro área de investigación es el diseño de índices eficientes para estos nuevos modelos de bases de datos.Eje: Base de datos y minería de datosRed de Universidades con Carreras en Informática (RedUNCI

A Herpes Simplex Virus Type 2 Deleted for Glycoprotein D Enables Dendritic Cells to Activate CD4+ and CD8+ T Cells

Herpes simplex virus type 2 (HSV-2) is highly prevalent in the human population producing significant morbidity, mainly because of the generation of genital ulcers and neonatal encephalitis. Additionally, HSV-2 infection significantly increases the susceptibility of the host to acquire HIV and promotes the shedding of the latter in the coinfected. Despite numerous efforts to create a vaccine against HSV-2, no licensed vaccines are currently available. A long-standing strategy, based on few viral glycoproteins combined with adjuvants, recently displayed poor results in a Phase III clinical study fueling exploration on the development of mutant HSV viruses that are attenuated in vivo and elicit protective adaptive immune components, such as antiviral antibodies and T cells. Importantly, such specialized antiviral immune components are likely induced and modulated by dendritic cells, professional antigen presenting cells that process viral antigens and present them to T cells. However, HSV interferes with several functions of DCs and ultimately induces their death. Here, we propose that for an attenuated mutant virus to confer protective immunity against HSV in vivo based on adaptive immune components, such virus should also be attenuated in dendritic cells to promote a robust and effective antiviral response. We provide a background framework for this idea, considerations, as well as the means to assess this hypothesis. Addressing this hypothesis may provide valuable insights for the development of novel, safe, and effective vaccines against herpes simplex viruses

Pharmacological Induction of Heme Oxygenase-1 Impairs Nuclear Accumulation of Herpes Simplex Virus Capsids upon Infection

Heme oxygenase-1 (HO-1) is an inducible enzyme that is expressed in response to physical and chemical stresses, such as ultraviolet radiation, hyperthermia, hypoxia, reactive oxygen species (ROS), as well as cytokines, among others. Its activity can be positively modulated by cobalt protoporphyrin (CoPP) and negatively by tin protoporphirin (SnPP). Once induced, HO-1 degrades iron-containing heme into ferrous iron (Fe2+), carbon monoxide (CO) and biliverdin. Importantly, numerous products of HO-1 are cytoprotective with anti-apoptotic, anti-oxidant, anti-inflammatory, and anti-cancer effects. The products of HO-1 also display antiviral properties against several viruses, such as the human immunodeficiency virus (HIV), influenza, hepatitis B, hepatitis C, and Ebola virus. Here, we sought to assess the effect of modulating HO-1 activity over herpes simplex virus type 2 (HSV-2) infection in epithelial cells and neurons. There are no vaccines against HSV-2 and treatment options are scarce in the immunosuppressed, in which drug-resistant variants emerge. By using HSV strains that encode structural and non-structural forms of the green fluorescent protein (GFP), we found that pharmacological induction of HO-1 activity with CoPP significantly decreases virus plaque formation and the expression of virus-encoded genes in epithelial cells as determined by flow cytometry and western blot assays. CoPP treatment did not affect virus binding to the cell surface or entry into the cytoplasm, but rather downstream events in the virus infection cycle. Furthermore, we observed that treating cells with a CO-releasing molecule (CORM-2) recapitulated some of the anti-HSV effects elicited by CoPP. Taken together, these findings indicate that HO-1 activity interferes with the replication cycle of HSV and that its antiviral effects can be recapitulated by CO

BCG-Based Vaccines Elicit Antigen-Specific Adaptive and Trained Immunity against SARS-CoV-2 and <i>Andes orthohantavirus</i>

Background:Mycobacterium bovis Bacillus Calmette-Guérin (BCG) is a live attenuated vaccine mainly administered to newborns and used for over 100 years to prevent the disease caused by Mycobacterium tuberculosis (M. tb). This vaccine can induce immune response polarization towards a Th1 profile, which is desired for counteracting M. tb, other mycobacteria, and unrelated intracellular pathogens. The vaccine BCG has been used as a vector to express recombinant proteins and has been shown to protect against several diseases, particularly respiratory viruses. Methods: BCG was used to develop recombinant vaccines expressing either the Nucleoprotein from SARS-CoV-2 or Andes orthohantavirus. Mice were immunized with these vaccines with the aim of evaluating the safety and immunogenicity parameters. Results: Immunization with two doses of 1 × 108 CFU or one dose of 1 × 105 CFU of these BCGs was safe in mice. A statistically significant cellular immune response was induced by both formulations, characterized as the activation of CD4+ and CD8+ T cells. Stimulation with unrelated antigens resulted in increased expression of activation markers by T cells and secretion of IL-2 and IFN-γ, while increased secretion of IL-6 was found for both recombinant vaccines; all of these parameters related to a trained immunity profile. The humoral immune response elicited by both vaccines was modest, but further exposure to antigens could increase this response. Conclusions: The BCG vaccine is a promising platform for developing vaccines against different pathogens, inducing a marked antigen-specific immune response