Endothelial Cell Proteomic Response to Rickettsia conorii Infection Reveals Activation of the Janus Kinase (JAK)-Signal Transducer and Activator of Transcription (STAT)-Inferferon Stimulated Gene (ISG)15 Pathway and Reprogramming Plasma Membrane Integrin/Cadherin Signaling.

Rickettsia conorii is the etiologic agent of Mediterranean spotted fever, a re-emerging infectious disease with significant mortality. This Gram-negative, obligately intracellular pathogen is transmitted via tick bites, resulting in disseminated vascular endothelial cell infection with vascular leakage. In the infected human, Rickettsia conorii infects endothelial cells, stimulating expression of cytokines and pro-coagulant factors. However, the integrated proteomic response of human endothelial cells to R. conorii infection is not known. In this study, we performed quantitative proteomic profiling of primary human umbilical vein endothelial cells (HUVECs) with established R conorii infection versus those stimulated with endotoxin (LPS) alone. We observed differential expression of 55 proteins in HUVEC whole cell lysates. Of these, we observed induction of signal transducer and activator of transcription (STAT)1, MX dynamin-like GTPase (MX1), and ISG15 ubiquitin-like modifier, indicating activation of the JAK-STAT signaling pathway occurs in R. conorii-infected HUVECs. The down-regulated proteins included those involved in the pyrimidine and arginine biosynthetic pathways. A highly specific biotinylated cross-linking enrichment protocol was performed to identify dysregulation of 11 integral plasma membrane proteins that included up-regulated expression of a sodium/potassium transporter and down-regulation of α-actin 1. Analysis of Golgi and soluble Golgi fractions identified up-regulated proteins involved in platelet-endothelial adhesion, phospholipase activity, and IFN activity. Thirty four rickettsial proteins were identified with high confidence in the Golgi, plasma membrane, or secreted protein fractions. The host proteins associated with rickettsial infections indicate activation of interferon-STAT signaling pathways; the disruption of cellular adhesion and alteration of antigen presentation pathways in response to rickettsial infections are distinct from those produced by nonspecific LPS stimulation. These patterns of differentially expressed proteins suggest mechanisms of pathogenesis as well as methods for diagnosis and monitoring Rickettsia infections.

Phenotype of the anti-Rickettsia CD8(+) T cell response suggests cellular correlates of protection for the assessment of novel antigens.

The obligately intracellular bacteria Rickettsia infect endothelial cells and cause systemic febrile diseases that are potentially lethal. No vaccines are currently available and current knowledge of the effective immune response is limited. Natural and experimental rickettsial infections provide strong and cross-protective cellular immunity if the infected individual survives the acute infection. Although resistance to rickettsial infections is attributed to the induction of antigen-specific T cells, particularly CD8(+) T cells, the identification and validation of correlates of protective cellular immunity against rickettsial infections, an important step toward vaccine validation, remains a gap in this field. Here, we show that after a primary challenge with Rickettsia typhi in the C3H mouse model, the peak of anti-Rickettsia CD8(+) T cell-mediated responses occurs 7 days post-infection (dpi), which coincides with the beginning of rickettsial clearance. At this time point, both effector-type and memory-type CD8(+) T cells are present, suggesting that 7 dpi is a valid time point for the assessment of CD8(+) T cell responses of mice previously immunized with protective antigens. Based on our results, we suggest four correlates of cellular protection for the assessment of protective rickettsial antigens: (1) production of IFN-γ by antigen-experienced CD3(+)CD8(+)CD44(high) cells, (2) production of Granzyme B by CD27(low)CD43(low) antigen-experienced CD8(+) T cells, (3) generation of memory-type CD8(+) T cells [Memory Precursor Effector Cells (MPECs), as well as CD127(high)CD43(low), and CD27(high)CD43(low) CD8(+) T cells], and (4) generation of effector-like memory CD8(+) T cells (CD27(low)CD43(low)). We propose that these correlates could be useful for the general assessment of the quality of the CD8(+) T cell immune response induced by novel antigens with potential use in a vaccine against Rickettsia.

Discovery of novel cross-protective Rickettsia prowazekii T-cell antigens using a combined reverse vaccinology and in vivo screening approach.

Rickettsial agents are some of the most lethal pathogens known to man. Among them, Rickettsia prowazekii is a select agent with potential use for bioterrorism; yet, there is no anti-Rickettsia vaccine commercially available. Owing to the obligate intracellular lifestyle of rickettsiae, CD8(+) T cells are indispensable for protective cellular immunity. Furthermore, T cells can mediate cross-protective immunity between different pathogenic Rickettsia, a finding consistent with the remarkable similarity among rickettsial genomes. However, Rickettsia T cell antigens remain unidentified. In the present study, we report an algorithm that allowed us to identify and validate four novel R. prowazekii vaccine antigen candidates recognized by CD8(+) T cells from a set of twelve in silico-defined protein targets. Our results highlight the importance of combining proteasome-processing as well as MHC class-I-binding predictions. The novel rickettsial vaccine candidate antigens, RP778, RP739, RP598, and RP403, protected mice against a lethal challenge with Rickettsia typhi, which is indicative of cross-protective immunity within the typhus group rickettsiae. Together, our findings validate a reverse vaccinology approach as a viable strategy to identify protective rickettsial antigens and highlight the feasibility of a subunit vaccine that triggers T-cell-mediated cross-protection among diverse rickettsiae.

Frequency and clinical manifestations of dengue in urban medellin, Colombia.

A dengue fever surveillance study was conducted at three medical facilities located in the low-income district of San Javier in Medellin, Colombia. During March 2008 to 2009, 781 patients with fever regardless of chief complaint were recruited for acute dengue virus infection testing. Of the 781 tested, 73 (9.3%) were positive for dengue infection. Serotypes DENV-2 (77%) and -3 (23%) were detected by PCR. One patient met the diagnostic criteria for dengue hemorrhagic fever. Only 3 out of 73 (4.1%) febrile subjects testing positive for dengue infection were diagnosed with dengue fever by the treating physician. This study confirms dengue virus as an important cause of acute febrile illness in Medellin, Colombia, but it is difficult to diagnose without dengue diagnostic testing.

A human lung xenograft mouse model of Nipah virus infection.

Nipah virus (NiV) is a member of the genus Henipavirus (family Paramyxoviridae) that causes severe and often lethal respiratory illness and encephalitis in humans with high mortality rates (up to 92%). NiV can cause Acute Lung Injury (ALI) in humans, and human-to-human transmission has been observed in recent outbreaks of NiV. While the exact route of transmission to humans is not known, we have previously shown that NiV can efficiently infect human respiratory epithelial cells. The molecular mechanisms of NiV-associated ALI in the human respiratory tract are unknown. Thus, there is an urgent need for models of henipavirus infection of the human respiratory tract to study the pathogenesis and understand the host responses. Here, we describe a novel human lung xenograft model in mice to study the pathogenesis of NiV. Following transplantation, human fetal lung xenografts rapidly graft and develop mature structures of adult lungs including cartilage, vascular vessels, ciliated pseudostratified columnar epithelium, and primitive "air" spaces filled with mucus and lined by cuboidal to flat epithelium. Following infection, NiV grows to high titers (10(7) TCID50/gram lung tissue) as early as 3 days post infection (pi). NiV targets both the endothelium as well as respiratory epithelium in the human lung tissues, and results in syncytia formation. NiV infection in the human lung results in the production of several cytokines and chemokines including IL-6, IP-10, eotaxin, G-CSF and GM-CSF on days 5 and 7 pi. In conclusion, this study demonstrates that NiV can replicate to high titers in a novel in vivo model of the human respiratory tract, resulting in a robust inflammatory response, which is known to be associated with ALI. This model will facilitate progress in the fundamental understanding of henipavirus pathogenesis and virus-host interactions; it will also provide biologically relevant models for other respiratory viruses.

Discovery of a protective Rickettsia prowazekii antigen recognized by CD8+ T cells, RP884, using an in vivo screening platform.

Rickettsia prowazekii has been tested for biological warfare due to the high mortality that it produces after aerosol transmission of very low numbers of rickettsiae. Epidemic typhus, the infection caused by these obligately intracellular bacteria, continues to be a threat because it is difficult to diagnose due to initial non-specific symptoms and the lack of commercial diagnostic tests that are sensitive and specific during the initial clinical presentation. A vaccine to prevent epidemic typhus would constitute an effective deterrent to the weaponization of R. prowazekii; however, an effective and safe vaccine is not currently available. Due to the cytoplasmic niche of Rickettsia, CD8(+) T-cells are critical effectors of immunity; however, the identification of antigens recognized by these cells has not been systematically addressed. To help close this gap, we designed an antigen discovery strategy that uses cell-based vaccination with antigen presenting cells expressing microbe's proteins targeted to the MHC class I presentation pathway. We report the use of this method to discover a protective T-cell rickettsial antigen, RP884, among a test subset of rickettsial proteins.

A humanized mouse model of tuberculosis.

Mycobacterium tuberculosis (M.tb) is the second leading infectious cause of death worldwide and the primary cause of death in people living with HIV/AIDS. There are several excellent animal models employed to study tuberculosis (TB), but many have limitations for reproducing human pathology and none are amenable to the direct study of HIV/M.tb co-infection. The humanized mouse has been increasingly employed to explore HIV infection and other pathogens where animal models are limiting. Our goal was to develop a small animal model of M.tb infection using the bone marrow, liver, thymus (BLT) humanized mouse. NOD-SCID/γc(null) mice were engrafted with human fetal liver and thymus tissue, and supplemented with CD34(+) fetal liver cells. Excellent reconstitution, as measured by expression of the human CD45 pan leukocyte marker by peripheral blood populations, was observed at 12 weeks after engraftment. Human T cells (CD3, CD4, CD8), as well as natural killer cells and monocyte/macrophages were all observed within the human leukocyte (CD45(+)) population. Importantly, human T cells were functionally competent as determined by proliferative capacity and effector molecule (e.g. IFN-γ, granulysin, perforin) expression in response to positive stimuli. Animals infected intranasally with M.tb had progressive bacterial infection in the lung and dissemination to spleen and liver from 2-8 weeks post infection. Sites of infection in the lung were characterized by the formation of organized granulomatous lesions, caseous necrosis, bronchial obstruction, and crystallization of cholesterol deposits. Human T cells were distributed throughout the lung, liver, and spleen at sites of inflammation and bacterial growth and were organized to the periphery of granulomas. These preliminary results demonstrate the potential to use the humanized mouse as a model of experimental TB.

Detección de DNA de herpesvirus equino tipos 1 y 4 en mononucleares de sangre periférica y ganglio trigémino de equinos. Infección, latencia y una aproximación a la neuropatogénesis de la cepa circulante / Detecção de DNA tipos de herpesvírus eqüino 1 e 4 nas células mononucleares do sangue periférico e os gânglios trigémeo de cavalos. Infecção, latência e de uma abordagem para o neuropatogénesis da cepa circulante / Equine herpesvirus 1 and 4 DNA detection in peripheral blood mononuclear cells and trigeminal ganglion of equines: Infection, latency and approximation to neuropathogenesis of the strain

La infección primaria por Herpesvirus Equino tipos 1 y 4 (HVE-1 y HVE-4) se inicia en el tracto respiratorio superior; luego se produce una viremia primaria en la que intervienen linfocitos B y T, la cual le permite al virus alcanzar otros sistemas orgánicos y producir abortos en el último tercio de la gestación, muerte neonatal de potros y síndromes neurológicos, principalmente por causa del HVE-1. Debido al hallazgo de anticuerpos contra HVE-1 y HVE-4 en caballos de dos departamentos de Colombia, el propósito de este estudio fue detectar la presencia del genoma viral en Mononucleares de Sangre Periférica (MNSP) de caballos seropositivos para HVE-1 y HVE-4 y en ganglios trigéminos de equinos en una planta de faenado del departamento de Antioquia. Por medio de una PCR semianidada se amplificaron los genes que codifican por las glicoproteína Hs (gH) de HVE-1 y B (gB) de HVE-4. El 28 y el 19% de los MNSP contenían el gen de la gH y de la gB, respectivamente. En el 57.8 y 47.7% de los ganglios trigéminos evaluados se logró amplificar los genes gH y gB, respectivamente. Para determinar si la cepa de HVE-1 circulante en el departamento de Antioquia poseía potencial neuropatogénico, se amplificó y secuenció el gen de la DNA polimerasa viral, que puede presentar una mutación asociada con neuropatogénesis. Sin embargo, ninguna de las cepas secuenciadas poseía dicha mutación. Los resultados confirman la presencia de la infección por HVE -1 y HVE-4 en el departamento de Antioquia, lo que sugiere que existen animales con infección latente que podrían ser una fuente de infección para otros animales susceptibles

The infection with Equine Herpesvirus types 1 and 4 (EHV-1 and EHV-4) occurs at the upper respiratory tract. Soon after this takes place a primary cell associated viremia to peripheral blood mononuclear cells (PBMC, mainly on B and T lymphocytes), which allows the virus to reach other organic systems and production of abortions in the last third of gestation, neonatal foal death and neurological syndromes. After primary infection the animals remain latently infected for all the life. Because the presence of antibodies for EHV-1 and EHV-4 in plasma and serum of horses of two departments of Colombia was demonstrated, the objective of the present study as to demonstrate the presence of the viral genome in PBMC from horses diagnosed seropositive for EHV-1 and EHV-4, and in trigeminal ganglion of equines from a slaughterhouse of the Department of Antioquia. By means of a semi-nested PCR, the gene codifying for glycoprotein H (gH) of EHV-1 and gB of EHV-4 were amplified. In PBMC 28 and 19% of gH and of gB amplification were found, respectively; whereas in trigeminal ganglion 57.8 and 47.7% were amplified for gH and gB, respectively. With the aim of assessing whether the circulating strain in the department of Antioquia had a neuropathogenic potential, we amplified and sent to sequencing the gene that encodes the viral DNA polymerase, which could has a mutation that has been associated with neuropathogenic potential. We found that the circulating viral strain in Antioquia does not have such a mutation. The set of our results confirms that infection by EHV is present in the State of Antioquia, Colombia, and that there are equines latently infected which can be a source of infection for other susceptible horses.

A infecção primária por Herpesvirus Eqüino tipo 1 e 4 (HVE-1 e HVE-4) inicia no tracto respiratório superior; depois, há uma viremia primária envolvidos no B e linfócitos T, que permite que o vírus chegue a outros sistemas e produtos biológicos abortos no último terço da gestação, morte neonatal de potros e síndromes neurológicas, devido sobretudo ao facto de HVE-1. Devido à descoberta de anticorpos contra o HVE-1 e HVE-4 cavalos em dois departamentos da Colômbia, O objetivo deste estudo foi o de detectar a presença do genoma viral em MNSP cavalo seropositivos para HVE-1 e HVE-4 4 os gânglios do trigémeo de cavalos em um curativo na planta do departamento de Antioquia. Através de uma PCR semianidada foram amplificados genes codificantes para a glicoproteína Hs (GH) HVE-1 e B (GB) de HVE-4. Em 28 e 19% do MNSP contendo o gene para a GH e no Reino Unido, respectivamente. No 57,8 e 47,7% dos gânglios trigêmeo avaliados foi atingido amplificar genes GH e GB, respectivamente. Para determinar se a estirpe do HVE-1 circulantes no departamento de Antioquia tinha potencial neuropatogénico, foi amplificado e sequenciado o gene da DNA polimerase viral, que pode apresentar uma mutação associada com neuropatogénesis. No entanto, nenhuma das cepas seqüenciadas possuía essa mutação. Os resultados confirmam a presença de infecção e de HVE -1 HVE-4, no departamento de Antioquia, sugerindo que há animais com infecção latente que poderia ser uma fonte de infecção para outros animais sensíveis.

Evidencia serológica de la infección por herpesvirus equino tipos 1 y 4 en dos regiones de Colombia / Provas serológicas de infecção por equine herpesvirus 1 e 4, em duas regiões da Colômbia / Serologic evidence of equine herpesvirus 1 and 4 infection in two regions of Colombia

Los herpesvirus equinos tipos 1 y 4 (HVE-1 y HVE-4) son agentes de distribución mundial y causa de graves pérdidas económicas. La infección primaria por ambos virus se produce en el tracto respiratorio, progresa a través de la mucosa y puede alcanzar otros sistemas orgánicos ocasionando abortos en el último tercio de gestación, muerte perinatal y síndromes neurológicos poco específicos. El HVE-1 está asociado principalmente con abortos, mientras que el HVE-4 se asocia con enfermedad respiratoria. Los animales afectados se recuperan sin tratamiento, pero permanecen infectados toda la vida. En 2001 se reportó en Colombia un aislamiento de HVE, pero hasta la fecha no se conoce ningún estudio que confirme y determine el tipo de herpesvirus aislado. El objetivo del presente trabajo fue realizar un estudio serológico para determinar la presencia de los HVE-1 y HVE-4 en equinos clínicamente sanos, no vacunados contra HVE. Para lograr nuestro objetivo se tomaron 139 muestras de suero de equinos de dos regiones de Colombia (Antioquia y Meta), a partir de las cuales se realizó una prueba de ELISA indirecta, para detectar la presencia de anticuerpos dirigidos contra la glicoproteína G del HVE-1 y HVE-4. Se encontró una seropositividad para HVE-4 del 98.7 y 96.6% en Antioquia y Meta respectivamente; para HVE-1, la seropositividad fue del 18.8% en el departamento de Antioquia y 33.3% en departamento del Meta. Este es el primer estudio que reporta seropositividad en equinos clínicamente sanos no vacunados en Colombia, lo cual sugiere la presencia del virus y su establecimiento en la población equina de las regiones evaluadas, y posiblemente de otras zonas de Colombia.

Equine herpesviruses 1 and 4 (EHV-1 and EHV-4) are world wide spread viruses that cause significant economic losses. The primary infection of both viruses occurs in the upper respiratory tract, it can progress trough the mucose and can cause abortions in the last third of pregnancy, neonatal foal death, and non specific neurological syndromes. The EHV-1 is associated mainly whit abortion whereas EHV-4 is more related to respiratory disease. Infected animals � rapidly overcome clinical symptoms but then remaininfected all the life. In 2001 the first isolation of an EHV was reported in Colombia, but up-to-date, there are no reports that confirm and determinethe type of isolated virus. The aim of the present work was to perform a serologic study in order to determine the presence of HVE-1 and HVE-4, in clinically healthy non-vaccinated horses. Serum samples n = 139 were drawn from healthy animals attwo regions of Colombia (Antioquia and Meta department); an indirect ELISA test was performed to evaluate the presence of antibodies recognizihg to glycoprotein G of EHV-1 and EHV-4. We found that 98.7 and 96.6% of sera in Antioquia and Meta respectively were positive for EHV-4; the positivity for EHV-1 in Antioquia and Meta were18.8 and 33.3% respectively. This isthe first study thatreports presence of antibodies to EHV-1 and EHV-4 in clinically healthy non-vaccinated horses in Colombia. These results suggest the establishment of the virus in the equine population of the studied regions and possibly in other areas of the country.

O herpesvirus eqüino tipo-1 e -4 (HVE-1 e HVE-4) são os agentes de distribuição mundial e causam graves prejuízos econômicos. A infecção primária por ambos os vírus ocorre no trato respiratório, progredindo através da mucosa e podem atingir outros sistemas orgânicos causando abortos no último terço da gestação, morte perinatal e não-específica síndromes neurológicas. O HVE-1 é principalmente associado a abortos, enquanto o HVE-4 está associado a doenças respiratórias. Os animais afectados recuperar sem tratamento, mas permanecem infectados vida. Em 2001, foi relatada na Colômbia isolamento de HVE, mas até agora não teve conhecimento de qualquer estudo para confirmar e identificar o tipo de herpesvírus isolados. O objetivo deste estudo foi o de realizar um levantamento sorológico para determinar a presença de HVE-1 e HVE-4 em cavalos clinicamente saudável, não vacinadas contra o HVE. Para alcançar nosso objetivo teve 139 amostras de soro de cavalos em duas regiões da Colômbia (Antioquia e Meta), de onde foi feito um teste Elisa indireta, para detectar a presença de anticorpos dirigidos contra a glicoproteína G da HVE -1 e da HVE-4. Para HVE-4 houve uma soropositividade de 98.7 e de 96.6% em Antioquia e Meta, respectivamente, para HVE-1, soropositividade foi 18.8% no departamento de Antioquia e de 33.3% no departamento de Meta. Este é o primeiro estudo que relatou soropositividade em cavalos clinicamente saudáveis não vacinados, na Colômbia, o que sugere a presença de vírus e seu lugar na eqüina população das regiões avaliadas e, possivelmente, de outras partes da Colômbia.

Diketo acids derivatives as integrase inhibitors: the war against the acquired immunodeficiency syndrome.

Since the human immunodeficiency virus was identified as etiological agent of the acquired immunodeficiency syndrome, great advances have been accomplished in the therapeutic field leading to reduced morbidity and mortality among infected patients. However, the high mutation rate of the viral genome generates strains resistant to multiple drugs, pointing to the importance of finding new therapeutic targets. Among the HIV structural genes, the POL gene codes for three essential enzymes: reverse transcriptase, protease, and integrase; nineteen of the twenty drugs currently approved by the Food and Drug Administration to treat this viral infection, inhibit the reverse transcriptase and the protease. Although intense research has been carried out in this area during the last 10 years, HIV integrase inhibitors are not yet approved for clinical use; however the fact that presence of this enzyme is a sine qua non for a productive HIV life cycle joined to its unique properties makes it a promissory target for anti-HIV therapy. Many compounds have been claimed to inhibit integrase in vitro; however, few of them have proven to have antiviral activity and low cytotoxicity in cell systems. Diketoacid derivatives are the most promising integrase inhibitors so far reported. Initially discovered independently by Shionogi & Co. and the Merck Research Laboratories, these compounds are highly specific for the integrase with potent antiviral activity in vitro and in vivo, and low cytotoxicity in cell cultures. Some of these compounds have recently entered clinical trials. Due to the high relevance of integrase inhibitors, and specifically of diketoacid derivatives, we review the latest findings and patents in this important field of research.