Intensified and protective CD4+ T cell immunity in mice with anti-dendritic cell HIV gag fusion antibody vaccine

Current human immunodeficiency virus (HIV) vaccine approaches emphasize prime boost strategies comprising multiple doses of DNA vaccine and recombinant viral vectors. We are developing a protein-based approach that directly harnesses principles for generating T cell immunity. Vaccine is delivered to maturing dendritic cells in lymphoid tissue by engineering protein antigen into an antibody to DEC-205, a receptor for antigen presentation. Here we characterize the CD4+ T cell immune response to HIV gag and compare efficacy with other vaccine strategies in a single dose. DEC-205-targeted HIV gag p24 or p41 induces stronger CD4+ T cell immunity relative to high doses of gag protein, HIV gag plasmid DNA, or recombinant adenovirus-gag. High frequencies of interferon (IFN)-γ- and interleukin 2-producing CD4 + T cells are elicited, including double cytokine-producing cells. In addition, the response is broad because the primed mice respond to an array of peptides in different major histocompatibility complex haplotypes. Long-lived T cell memory is observed. After subcutaneous vaccination, CD4+ and IFN-γ-dependent protection develops to a challenge with recombinant vaccinia-gag virus at a mucosal surface, the airway. We suggest that a DEC-targeted vaccine, in part because of an unusually strong and protective CD4+ T cell response, will improve vaccine efficacy as a stand-alone approach or with other modalities

Granulocyte Colony-Stimulating Factor Protects Mice during Respiratory Virus Infections

A burst in the production of pro-inflammatory molecules characterizes the beginning of the host response to infection. Cytokines, chemokines, and growth factors work in concert to control pathogen replication and activate innate and adaptive immune responses. Granulocyte colony-stimulating factor (G-CSF) mobilizes and activates hematopoietic cells from the bone marrow, and it has been shown to mediate the generation of effective immunity against bacterial and fungal infections. G-CSF is produced at high levels in the lungs during infection with influenza and parainfluenza viruses, but its role during these infections is unknown. Here we show that during infection of mice with a non-lethal dose of influenza or Sendai virus, G-CSF promotes the accumulation of activated Ly6G+ granulocytes that control the extent of the lung pro-inflammatory response. Remarkably, these G-CSF-mediated effects facilitate viral clearance and sustain mouse survival

Buying Time—The Immune System Determinants of the Incubation Period to Respiratory Viruses

Respiratory viruses cause disease in humans characterized by an abrupt onset of symptoms. Studies in humans and animal models have shown that symptoms are not immediate and appear days or even weeks after infection. Since the initial symptoms are a manifestation of virus recognition by elements of the innate immune response, early virus replication must go largely undetected. The interval between infection and the emergence of symptoms is called the incubation period and is widely used as a clinical score. While incubation periods have been described for many virus infections the underlying mechanism for this asymptomatic phase has not been comprehensively documented. Here we review studies of the interaction between human pathogenic respiratory RNA viruses and the host with a particular emphasis on the mechanisms used by viruses to inhibit immunity. We discuss the concept of the “stealth phase”, defined as the time between infection and the earliest detectable inflammatory response. We propose that the “stealth phase” phenomenon is primarily responsible for the suppression of symptoms during the incubation period and results from viral antagonism that inhibits major pathways of the innate immune system allowing an extended time of unhindered virus replication

Copy-back viral genomes induce a cellular stress response that interferes with viral protein expression without affecting antiviral immunity

Antiviral responses are often accompanied by translation inhibition and formation of stress granules (SGs) in infected cells. However, the triggers for these processes and their role during infection remain subjects of active investigation. Copy-back viral genomes (cbVGs) are the primary inducers of the mitochondrial antiviral signaling (MAVS) pathway and antiviral immunity during Sendai virus (SeV) and respiratory syncytial virus (RSV) infections. The relationship between cbVGs and cellular stress during viral infections is unknown. Here, we show that SGs form during infections containing high levels of cbVGs, and not during infections with low levels of cbVGs. Moreover, using RNA fluorescent in situ hybridization to differentiate accumulation of standard viral genomes from cbVGs at a single-cell level during infection, we show that SGs form exclusively in cells that accumulate high levels of cbVGs. Protein kinase R (PKR) activation is increased during high cbVG infections and, as expected, is necessary for virus-induced SGs. However, SGs form independent of MAVS signaling, demonstrating that cbVGs induce antiviral immunity and SG formation through 2 independent mechanisms. Furthermore, we show that translation inhibition and SG formation do not affect the overall expression of interferon and interferon stimulated genes during infection, making the stress response dispensable for global antiviral immunity. Using live-cell imaging, we show that SG formation is highly dynamic and correlates with a drastic reduction of viral protein expression even in cells infected for several days. Through analysis of active protein translation at a single-cell level, we show that infected cells that form SGs show inhibition of protein translation. Together, our data reveal a new cbVG-driven mechanism of viral interference where cbVGs induce PKR-mediated translation inhibition and SG formation, leading to a reduction in viral protein expression without altering overall antiviral immunity

Accumulation of copy-back viral genomes during respiratory syncytial virus infection is preceded by diversification of the copy-back viral genome population followed by selection

RNA viruses generate nonstandard viral genomes during their replication, including viral genomes of the copy-back (cbVGs) type that cannot replicate in the absence of a standard virus. cbVGs play a crucial role in shaping virus infection outcomes due to their ability to interfere with virus replication and induce strong immune responses. However, despite their critical role during infection, the principles that drive the selection and evolution of cbVGs within a virus population are poorly understood. As cbVGs are dependent on the virus replication machinery to be generated and replicated, we hypothesized that host factors that affect virus replication exert selective pressure on cbVGs and drive their evolution within a virus population. To test this hypothesis, we used respiratory syncytial virus (RSV) as a model and took an experimental evolution approach by serially passaging RSV in immune-competent human lung adenocarcinoma A549 control and immune-deficient A549 Signal transducer and activator of transcription 1 (STAT1) KO cells, which allow higher levels of virus replication. As predicted, we observed that virus populations accumulated higher amounts of cbVGs in the more permissive A549 STAT1 KO cells over time; however, unexpectedly, the predominant cbVG species after passages in the two conditions were different. While A549 STAT1 KO cells accumulated relatively short cbVGs, A549 control cells mainly contained cbVGs of much longer predicted size, which have not been described previously. These long cbVGs were predominant at first in both cell line

The Virion Host Shut-Off (vhs) Protein Blocks a TLR-Independent Pathway of Herpes Simplex Virus Type 1 Recognition in Human and Mouse Dendritic Cells

Molecular pathways underlying the activation of dendritic cells (DCs) in response to Herpes Simplex Virus type 1 (HSV-1) are poorly understood. Removal of the HSV virion host shut-off (vhs) protein relieves a block to DC activation observed during wild-type infection. In this study, we utilized a potent DC stimulatory HSV-1 recombinant virus lacking vhs as a tool to investigate the mechanisms involved in the activation of DCs by HSV-1. We report that the release of pro-inflammatory cytokines by conventional DC (cDC) during HSV-1 infection is triggered by both virus replication-dependent and replication-independent pathways. Interestingly, while vhs is capable of inhibiting the release of cytokines during infection of human and mouse cDCs, the secretion of cytokines by plasmacytoid DC (pDC) is not affected by vhs. These data prompted us to postulate that infection of cDCs by HSV triggers a TLR independent pathway for cDC activation that is susceptible to blockage by the vhs protein. Using cDCs isolated from mice deficient in both the TLR adaptor protein MyD88 and TLR3, we show that HSV-1 and the vhs-deleted virus can activate cDCs independently of TLR signaling. In addition, virion-associated vhs fails to block cDC activation in response to treatment with TLR agonists, but it efficiently blocked cDC activation triggered by the paramyxoviruses Sendai Virus (SeV) and Newcastle Disease Virus (NDV). This block to SeV- and NDV-induced activation of cDC resulted in elevated SeV and NDV viral gene expression indicating that infection with HSV-1 enhances the cell's susceptibility to other pathogens through the action of vhs. Our results demonstrate for the first time that a viral protein contained in the tegument of HSV-1 can block the induction of DC activation by TLR-independent pathways of viral recognition

Taller de ambientación universitaria de la Facultad de Ciencias Agrarias y Forestales de la Universidad Nacional de La Plata: análisis de encuestas iniciales

La elección de la carrera universitaria de los alumnos que ingresan a la Facultad de Ciencias Agrarias y Forestales de la Universidad Nacional de La Plata se ve afectada por factores culturales y socioeconómicos. Con el propósito de cuantificar los datos relevados por la Unidad Pedagógica de la FCAyF referidos a estos temas y conformar un diagnóstico académico acerca del tipo de estudiantes que se incorporan a esta facultad y la detección de los posibles factores involucrados en el inicio de la formación universitaria, se plantearon los siguientes objetivos: procesar y analizar los datos registrados en las encuestas iniciales aplicadas a los alumnos ingresantes de los años 2009, 2010 y 2011 (TAU y Curso de Nivelación), y categorizar los resultados obtenidos sobre la base de distintos criterios de análisis. La encuesta está compuesta por ocho preguntas de opción binaria o múltiple y 10 preguntas abiertas. Los resultados se presentan en función de las siguientes categorías: carrera de elección, características sociodemográficas, valoración de la experiencia escolar, dominio de informáticos e idiomas, campo de ejercicio profesional, y personales. Los resultados son presentados en función del porcentaje de ocurrencia de las categorías descriptas en la encuesta inicial.Eje temático 1: Problemáticas y alternativas de mejora de la enseñanza b - Las estrategias de admisión e inclusión en el ingreso y los primeros añosFacultad de Ciencias Agrarias y Forestale

Taller de ambientación universitaria de la Facultad de Ciencias Agrarias y Forestales de la Universidad Nacional de La Plata: análisis de encuestas iniciales

La elección de la carrera universitaria de los alumnos que ingresan a la Facultad de Ciencias Agrarias y Forestales de la Universidad Nacional de La Plata se ve afectada por factores culturales y socioeconómicos. Con el propósito de cuantificar los datos relevados por la Unidad Pedagógica de la FCAyF referidos a estos temas y conformar un diagnóstico académico acerca del tipo de estudiantes que se incorporan a esta facultad y la detección de los posibles factores involucrados en el inicio de la formación universitaria, se plantearon los siguientes objetivos: procesar y analizar los datos registrados en las encuestas iniciales aplicadas a los alumnos ingresantes de los años 2009, 2010 y 2011 (TAU y Curso de Nivelación), y categorizar los resultados obtenidos sobre la base de distintos criterios de análisis. La encuesta está compuesta por ocho preguntas de opción binaria o múltiple y 10 preguntas abiertas. Los resultados se presentan en función de las siguientes categorías: carrera de elección, características sociodemográficas, valoración de la experiencia escolar, dominio de informáticos e idiomas, campo de ejercicio profesional, y personales. Los resultados son presentados en función del porcentaje de ocurrencia de las categorías descriptas en la encuesta inicial.Eje temático 1: Problemáticas y alternativas de mejora de la enseñanza b - Las estrategias de admisión e inclusión en el ingreso y los primeros añosFacultad de Ciencias Agrarias y Forestale

Taller de ambientación universitaria de la Facultad de Ciencias Agrarias y Forestales de la Universidad Nacional de La Plata: análisis de encuestas iniciales

La elección de la carrera universitaria de los alumnos que ingresan a la Facultad de Ciencias Agrarias y Forestales de la Universidad Nacional de La Plata se ve afectada por factores culturales y socioeconómicos. Con el propósito de cuantificar los datos relevados por la Unidad Pedagógica de la FCAyF referidos a estos temas y conformar un diagnóstico académico acerca del tipo de estudiantes que se incorporan a esta facultad y la detección de los posibles factores involucrados en el inicio de la formación universitaria, se plantearon los siguientes objetivos: procesar y analizar los datos registrados en las encuestas iniciales aplicadas a los alumnos ingresantes de los años 2009, 2010 y 2011 (TAU y Curso de Nivelación), y categorizar los resultados obtenidos sobre la base de distintos criterios de análisis. La encuesta está compuesta por ocho preguntas de opción binaria o múltiple y 10 preguntas abiertas. Los resultados se presentan en función de las siguientes categorías: carrera de elección, características sociodemográficas, valoración de la experiencia escolar, dominio de informáticos e idiomas, campo de ejercicio profesional, y personales. Los resultados son presentados en función del porcentaje de ocurrencia de las categorías descriptas en la encuesta inicial.Eje temático 1: Problemáticas y alternativas de mejora de la enseñanza b - Las estrategias de admisión e inclusión en el ingreso y los primeros añosFacultad de Ciencias Agrarias y Forestale