Zika virus (ZIKV) is a significant threat to pregnant women and fetuses as it can cause severe bi... more Zika virus (ZIKV) is a significant threat to pregnant women and fetuses as it can cause severe birth defects and congenital neurodevelopmental disorders, referred to as congenital Zika syndrome (CZS). Thus, a safe and effective ZIKV vaccine for pregnant women to prevent in utero ZIKV infection is of utmost importance. Murine models of ZIKV infection are limited by the fact that immunocompetent mice are resistant to ZIKV infection. As such, interferon-deficient mice have been used in some preclinical studies to test the efficacy of ZIKV vaccine candidates against lethal virus challenge. However, interferon-deficient mouse models have limitations in assessing the immunogenicity of vaccines, necessitating the use of immunocompetent mouse pregnancy models. Using the human stat2 knock-in (hSTAT2KI) mouse pregnancy model, we show that vaccination with a purified formalin-inactivated Zika virus vaccine (ZPIV) prior to pregnancy successfully prevented vertical transmission. In addition, mat...
Zika virus (ZIKV) infection during pregnancy causes severe developmental defects in newborns, ter... more Zika virus (ZIKV) infection during pregnancy causes severe developmental defects in newborns, termed congenital Zika syndrome (CZS). Factors contributing to a surge in ZIKV-associated CZS are poorly understood. One possibility is that ZIKV may exploit the antibody-dependent enhancement of infection mechanism, mediated by cross-reactive antibodies from prior dengue virus (DENV) infection, which may exacerbate ZIKV infection during pregnancy. In this study, we investigated the impact of prior DENV infection or no DENV infection on ZIKV pathogenesis during pregnancy in a total of four female common marmosets with five or six fetuses per group. The results showed that negative-sense viral RNA copies increased in the placental and fetal tissues of DENV-immune dams but not in DENV-naïve dams. In addition, viral proteins were prevalent in endothelial cells, macrophages, and neonatal Fc receptor–expressing cells in the placental trabeculae and in neuronal cells in the brains of fetuses from...
Zika virus (ZIKV) is a mosquito-borne arbovirus that can cause severe congenital birth defects. T... more Zika virus (ZIKV) is a mosquito-borne arbovirus that can cause severe congenital birth defects. The utmost goal of ZIKV vaccines is to prevent both maternal-fetal infection and congenital Zika syndrome. A Zika purified inactivated virus (ZPIV) was previously shown to be protective in non-pregnant mice and rhesus macaques. In this study, we further examined the efficacy of ZPIV against ZIKV infection during pregnancy in immunocompetent C57BL6 mice and common marmoset monkeys (Callithrix jacchus). We showed that, in C57BL/6 mice, ZPIV significantly reduced ZIKV-induced fetal malformations. Protection of fetuses was positively correlated with virus-neutralizing antibody levels. In marmosets, the vaccine prevented vertical transmission of ZIKV and elicited neutralizing antibodies that remained above a previously determined threshold of protection for up to 18 months. These proof-of-concept studies demonstrate ZPIV’s protective efficacy is both potent and durable and has the potential to...
ABSTRACTBackgroundSARS-CoV-2 infections have resulted in a global pandemic, but an antiviral ther... more ABSTRACTBackgroundSARS-CoV-2 infections have resulted in a global pandemic, but an antiviral therapy for this novel strain of coronavirus does not currently exist. The objective of our study was to investigate the antiviral potential of the nicotinic acetylcholine receptor (nACHR) agonist varenicline tartrate against SARS-CoV-2.MethodsWe assessed antiviral activity using in vitro human cell assays and we assessed in vivo efficacy in a rhesus macaque model.ResultsIn vitro studies found that varenicline tartrate, over a range of concentrations, reduced the infectivity of SARS-CoV-2 wildtype, alpha, and beta variants in Calu-3 cells and Caco-2 cells, with maintenance of cell viability. In vivo studies found that varenicline tartrate, administered as a nasal spray to rhesus macaques, reduced SARS-CoV-2 wildtype viral load and inhibited viral replication in the nasal mucosa and upper airway.ConclusionAlthough the study reported here was exploratory, we have confirmed that the nAChR agoni...
Fibrin, a product of the blood coagulation cascade, accompanies many type 1 immune responses, inc... more Fibrin, a product of the blood coagulation cascade, accompanies many type 1 immune responses, including delayed-type hypersensitivity, autoimmunity, and graft rejection. In those settings, fibrin is thought to exacerbate inflammation and disease. Here, we evaluate roles for coagulation during infection with Toxoplasma gondii, a pathogen whose control requires robust type 1 immunity. We establish that fibrin prevents infection-stimulated blood loss, thereby performing a protective function that is essential for survival. Remarkably, fibrin does not simply protect against vascular damage caused directly by the infectious agent, but rather, protects against hemorrhage evoked by interferon-�, a critical mediator of type 1 immunity. This finding, to our knowledge, is the first to document a beneficial role for coagulation during type 1 immunity, and suggests that fibrin deposition protects host tissue from collateral damage caused by the immune system as it combats infection. Key words:
Zika virus (ZIKV) infection during human pregnancy may cause diverse and serious congenital defec... more Zika virus (ZIKV) infection during human pregnancy may cause diverse and serious congenital defects in the developing fetus. Previous efforts to generate animal models of human ZIKV infection and clinical symptoms often involved manipulating mice to impair their Type I interferon (IFN) signaling, thereby allowing enhanced infection and vertical transmission of virus to the embryo. Here, we show that even pregnant mice competent to generate Type I IFN responses that can limit ZIKV infection nonetheless develop profound placental pathology and high frequency of fetal demise. We consistently found that maternal ZIKV exposure led to placental pathology and that ZIKV RNA levels measured in maternal, placental or embryonic tissues were not predictive of the pathological effects seen in the embryos. Placental pathology included trophoblast hyperplasia in the labyrinth, trophoblast giant cell necrosis in the junctional zone, and loss of embryonic vessels. Our findings suggest that, in this ...
Lawrence L. JohnsonFrank M. Szaba, Jonathan E. Boyson, Wangxue Chen and Stephen T. Smiley, Paula ... more Lawrence L. JohnsonFrank M. Szaba, Jonathan E. Boyson, Wangxue Chen and Stephen T. Smiley, Paula A. Lanthier, Kevin N. Couper,http://www.jimmunol.org/content/174/12/7904J Immunol€2005; 174:7904-7911; ;Referenceshttp://www.jimmunol.org/content/174/12/7904.full#ref-list-1This article cites 79 articles, 57 of which you can access for free at: Subscriptionshttp://jimmunol.org/subscriptionsInformation about subscribing to The Journal of Immunology is online at: Permissionshttp://www.aai.org/ji/copyright.htmlSubmit copyright permission requests at: Email Alertshttp://jimmunol.org/cgi/alerts/etocReceive free email-alerts when new articles cite this article. Sign up at:
ABSTRACTPlague is a rapidly lethal human disease caused by the bacteriumYersinia pestis. This stu... more ABSTRACTPlague is a rapidly lethal human disease caused by the bacteriumYersinia pestis. This study demonstrated that theY. pestisplasminogen activator Pla, a protease that promotes fibrin degradation, thwarts T cell-mediated defense against fully virulentY. pestis. Introducing a single point mutation into the active site of Pla suffices to render fully virulentY. pestissusceptible to primed T cells. Mechanistic studies revealed essential roles for fibrin during T cell-mediated defense against Pla-mutantY. pestis. Moreover, the efficacy of T cell-mediated protection against variousY. pestisstrains displayed an inverse relationship with their levels of Pla activity. Together, these data indicate that Pla functions to thwart fibrin-dependent T cell-mediated defense against plague. Other important human bacterial pathogens, including staphylococci, streptococci, and borrelia, likewise produce virulence factors that promote fibrin degradation. The discovery thatY. pestisthwarts T cell d...
Septic pneumonias resulting from bacterial infections of the lung are a leading cause of human de... more Septic pneumonias resulting from bacterial infections of the lung are a leading cause of human death worldwide. Little is known about the capacity of CD8 T cell-mediated immunity to combat these infections and the types of effector functions that may be most effective. Pneumonic plague is an acutely lethal septic pneumonia caused by the Gram-negative bacterium Yersinia pestis. We recently identified a dominant and protective Y. pestis antigen, YopE69-77, recognized by CD8 T cells in C57BL/6 mice. Here, we use gene-deficient mice, Ab-mediated depletion, cell transfers, and bone marrow chimeric mice to investigate the effector functions of YopE69-77-specific CD8 T cells and their relative contributions during pulmonary Y. pestis infection. We demonstrate that YopE69-77-specific CD8 T cells exhibit perforin-dependent cytotoxicity in vivo; however, perforin is dispensable for YopE69-77-mediated protection. In contrast, YopE69-77-mediated protection is severely impaired when production o...
Zika virus (ZIKV) is a significant threat to pregnant women and fetuses as it can cause severe bi... more Zika virus (ZIKV) is a significant threat to pregnant women and fetuses as it can cause severe birth defects and congenital neurodevelopmental disorders, referred to as congenital Zika syndrome (CZS). Thus, a safe and effective ZIKV vaccine for pregnant women to prevent in utero ZIKV infection is of utmost importance. Murine models of ZIKV infection are limited by the fact that immunocompetent mice are resistant to ZIKV infection. As such, interferon-deficient mice have been used in some preclinical studies to test the efficacy of ZIKV vaccine candidates against lethal virus challenge. However, interferon-deficient mouse models have limitations in assessing the immunogenicity of vaccines, necessitating the use of immunocompetent mouse pregnancy models. Using the human stat2 knock-in (hSTAT2KI) mouse pregnancy model, we show that vaccination with a purified formalin-inactivated Zika virus vaccine (ZPIV) prior to pregnancy successfully prevented vertical transmission. In addition, mat...
Zika virus (ZIKV) infection during pregnancy causes severe developmental defects in newborns, ter... more Zika virus (ZIKV) infection during pregnancy causes severe developmental defects in newborns, termed congenital Zika syndrome (CZS). Factors contributing to a surge in ZIKV-associated CZS are poorly understood. One possibility is that ZIKV may exploit the antibody-dependent enhancement of infection mechanism, mediated by cross-reactive antibodies from prior dengue virus (DENV) infection, which may exacerbate ZIKV infection during pregnancy. In this study, we investigated the impact of prior DENV infection or no DENV infection on ZIKV pathogenesis during pregnancy in a total of four female common marmosets with five or six fetuses per group. The results showed that negative-sense viral RNA copies increased in the placental and fetal tissues of DENV-immune dams but not in DENV-naïve dams. In addition, viral proteins were prevalent in endothelial cells, macrophages, and neonatal Fc receptor–expressing cells in the placental trabeculae and in neuronal cells in the brains of fetuses from...
Zika virus (ZIKV) is a mosquito-borne arbovirus that can cause severe congenital birth defects. T... more Zika virus (ZIKV) is a mosquito-borne arbovirus that can cause severe congenital birth defects. The utmost goal of ZIKV vaccines is to prevent both maternal-fetal infection and congenital Zika syndrome. A Zika purified inactivated virus (ZPIV) was previously shown to be protective in non-pregnant mice and rhesus macaques. In this study, we further examined the efficacy of ZPIV against ZIKV infection during pregnancy in immunocompetent C57BL6 mice and common marmoset monkeys (Callithrix jacchus). We showed that, in C57BL/6 mice, ZPIV significantly reduced ZIKV-induced fetal malformations. Protection of fetuses was positively correlated with virus-neutralizing antibody levels. In marmosets, the vaccine prevented vertical transmission of ZIKV and elicited neutralizing antibodies that remained above a previously determined threshold of protection for up to 18 months. These proof-of-concept studies demonstrate ZPIV’s protective efficacy is both potent and durable and has the potential to...
ABSTRACTBackgroundSARS-CoV-2 infections have resulted in a global pandemic, but an antiviral ther... more ABSTRACTBackgroundSARS-CoV-2 infections have resulted in a global pandemic, but an antiviral therapy for this novel strain of coronavirus does not currently exist. The objective of our study was to investigate the antiviral potential of the nicotinic acetylcholine receptor (nACHR) agonist varenicline tartrate against SARS-CoV-2.MethodsWe assessed antiviral activity using in vitro human cell assays and we assessed in vivo efficacy in a rhesus macaque model.ResultsIn vitro studies found that varenicline tartrate, over a range of concentrations, reduced the infectivity of SARS-CoV-2 wildtype, alpha, and beta variants in Calu-3 cells and Caco-2 cells, with maintenance of cell viability. In vivo studies found that varenicline tartrate, administered as a nasal spray to rhesus macaques, reduced SARS-CoV-2 wildtype viral load and inhibited viral replication in the nasal mucosa and upper airway.ConclusionAlthough the study reported here was exploratory, we have confirmed that the nAChR agoni...
Fibrin, a product of the blood coagulation cascade, accompanies many type 1 immune responses, inc... more Fibrin, a product of the blood coagulation cascade, accompanies many type 1 immune responses, including delayed-type hypersensitivity, autoimmunity, and graft rejection. In those settings, fibrin is thought to exacerbate inflammation and disease. Here, we evaluate roles for coagulation during infection with Toxoplasma gondii, a pathogen whose control requires robust type 1 immunity. We establish that fibrin prevents infection-stimulated blood loss, thereby performing a protective function that is essential for survival. Remarkably, fibrin does not simply protect against vascular damage caused directly by the infectious agent, but rather, protects against hemorrhage evoked by interferon-�, a critical mediator of type 1 immunity. This finding, to our knowledge, is the first to document a beneficial role for coagulation during type 1 immunity, and suggests that fibrin deposition protects host tissue from collateral damage caused by the immune system as it combats infection. Key words:
Zika virus (ZIKV) infection during human pregnancy may cause diverse and serious congenital defec... more Zika virus (ZIKV) infection during human pregnancy may cause diverse and serious congenital defects in the developing fetus. Previous efforts to generate animal models of human ZIKV infection and clinical symptoms often involved manipulating mice to impair their Type I interferon (IFN) signaling, thereby allowing enhanced infection and vertical transmission of virus to the embryo. Here, we show that even pregnant mice competent to generate Type I IFN responses that can limit ZIKV infection nonetheless develop profound placental pathology and high frequency of fetal demise. We consistently found that maternal ZIKV exposure led to placental pathology and that ZIKV RNA levels measured in maternal, placental or embryonic tissues were not predictive of the pathological effects seen in the embryos. Placental pathology included trophoblast hyperplasia in the labyrinth, trophoblast giant cell necrosis in the junctional zone, and loss of embryonic vessels. Our findings suggest that, in this ...
Lawrence L. JohnsonFrank M. Szaba, Jonathan E. Boyson, Wangxue Chen and Stephen T. Smiley, Paula ... more Lawrence L. JohnsonFrank M. Szaba, Jonathan E. Boyson, Wangxue Chen and Stephen T. Smiley, Paula A. Lanthier, Kevin N. Couper,http://www.jimmunol.org/content/174/12/7904J Immunol€2005; 174:7904-7911; ;Referenceshttp://www.jimmunol.org/content/174/12/7904.full#ref-list-1This article cites 79 articles, 57 of which you can access for free at: Subscriptionshttp://jimmunol.org/subscriptionsInformation about subscribing to The Journal of Immunology is online at: Permissionshttp://www.aai.org/ji/copyright.htmlSubmit copyright permission requests at: Email Alertshttp://jimmunol.org/cgi/alerts/etocReceive free email-alerts when new articles cite this article. Sign up at:
ABSTRACTPlague is a rapidly lethal human disease caused by the bacteriumYersinia pestis. This stu... more ABSTRACTPlague is a rapidly lethal human disease caused by the bacteriumYersinia pestis. This study demonstrated that theY. pestisplasminogen activator Pla, a protease that promotes fibrin degradation, thwarts T cell-mediated defense against fully virulentY. pestis. Introducing a single point mutation into the active site of Pla suffices to render fully virulentY. pestissusceptible to primed T cells. Mechanistic studies revealed essential roles for fibrin during T cell-mediated defense against Pla-mutantY. pestis. Moreover, the efficacy of T cell-mediated protection against variousY. pestisstrains displayed an inverse relationship with their levels of Pla activity. Together, these data indicate that Pla functions to thwart fibrin-dependent T cell-mediated defense against plague. Other important human bacterial pathogens, including staphylococci, streptococci, and borrelia, likewise produce virulence factors that promote fibrin degradation. The discovery thatY. pestisthwarts T cell d...
Septic pneumonias resulting from bacterial infections of the lung are a leading cause of human de... more Septic pneumonias resulting from bacterial infections of the lung are a leading cause of human death worldwide. Little is known about the capacity of CD8 T cell-mediated immunity to combat these infections and the types of effector functions that may be most effective. Pneumonic plague is an acutely lethal septic pneumonia caused by the Gram-negative bacterium Yersinia pestis. We recently identified a dominant and protective Y. pestis antigen, YopE69-77, recognized by CD8 T cells in C57BL/6 mice. Here, we use gene-deficient mice, Ab-mediated depletion, cell transfers, and bone marrow chimeric mice to investigate the effector functions of YopE69-77-specific CD8 T cells and their relative contributions during pulmonary Y. pestis infection. We demonstrate that YopE69-77-specific CD8 T cells exhibit perforin-dependent cytotoxicity in vivo; however, perforin is dispensable for YopE69-77-mediated protection. In contrast, YopE69-77-mediated protection is severely impaired when production o...
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