The simulation of the dynamics of viral infections by mathematical equations has been applied successfully to the study of viral infections during antiviral therapy. Standard models applied to viral hepatitis describe...The simulation of the dynamics of viral infections by mathematical equations has been applied successfully to the study of viral infections during antiviral therapy. Standard models applied to viral hepatitis describe the viral load decline in the f irst 2-4 wk of antiviral therapy, but do not adequately simulate the dynamics of viral infection for the following period. The hypothesis of a constant clearance rate of the infected cells provides an unrealistic estimation of the time necessary to reach the control or the clearance of hepatitis B virus (HBV)/ hepatitis C virus (HCV) infection. To overcome the problem, we have developed a new multiphasic model in which the immune system activity is modulated by a negative feedback caused by the infected cells reduction, and alanine aminotransferase kinetics serve as a surrogate marker of infected-cell clearance. By this approach, we can compute the dynamics of infected cells during the whole treatment course, and find a good correlation between the number of infected cells at the end of therapy and the long-term virological response in patients with chronic hepatitis C. The new model successfully describes the HBV infection dynamics far beyond the third month of antiviral therapy under the assumption that the sum of infected and non-infected cells remains roughly constant during therapy, and both target and infected cells concur in the hepatocyte turnover. In clinical practice, these new models will allow the development of simulators of treatment response that will be used as an "automatic pilot" for tailoring antiviral therapy in chronic hepatitis B as well as chronic hepatitis C patients.展开更多
Active host-pathogen interactions take place during infection of human immunodeficiency virus type 1 (HIV-1). Outcomes of these interactions determine the efficiency of viral infection and subsequent disease progressi...Active host-pathogen interactions take place during infection of human immunodeficiency virus type 1 (HIV-1). Outcomes of these interactions determine the efficiency of viral infection and subsequent disease progression. HIV- infected cells respond to viral invasion with various defensive strategies such as innate, cellular and humoral immune antiviral mechanisms. On the other hand, the virus has also developed various offensive tactics to suppress these host cellular responses. Among many of the viral offensive strategies, HIV-1 viral auxiliary proteins (Tat, Rev, Nef, Vif, Vpr and Vpu) play important roles in the host-pathogen interaction and thus have significant impacts on the outcome of HIV infection. One of the best examples is the interaction of Vif with a host cytidine deaminase APOBEC3G. Although specific roles of other auxiliary proteins are not as well described as Vif-APOBEC3G interaction, it is the goal of this brief review to summarize some of the preliminary findings with the hope to stimulate further discussion and investiga- tion in this exhilarating area of research.展开更多
The effect of maternal antibodies on the pathogenesis of avian reovirus （ARV） was studied in commercial and specific pathogen free broilers （SPF） using a real-time reverse transcriptase （RT）-polymerase chain rea...The effect of maternal antibodies on the pathogenesis of avian reovirus （ARV） was studied in commercial and specific pathogen free broilers （SPF） using a real-time reverse transcriptase （RT）-polymerase chain reaction （PCR） assay, along with the incidence and severity of morbidity, mortality, and gross lesions. ARV RNA was detected in cloacal swabs in both bird groups from the first day throughout the 21 days experiment. Commercial broiler chickens, which had high maternal antibodies against ARV, showed minimum clinical signs, gross lesions, and lower numbers of birds with viral RNA excretion, whereas specific pathogen free （SPF） broiler chickens, which did not have antibody against ARVs, had 30% mortality, more severe signs, and higher numbers of birds excreting viral RNA. The highest peak of SPF birds excreting viral RNA occurred during the time of maximum mortality. The protective effect of maternal antibody on ARV pathogenesis in broiler chickens correlated with the detection of ARV RNA using the real-time RT-PCR.展开更多
Verticillium dahliae is a soil-borne phytopathogenic fungus that causes vascular wilt disease in a broad range of hosts. This pathogen survives for many years in soil in the form ofmelanized microsclerotia. To investi...Verticillium dahliae is a soil-borne phytopathogenic fungus that causes vascular wilt disease in a broad range of hosts. This pathogen survives for many years in soil in the form ofmelanized microsclerotia. To investigate the melanin synthesis in V.. dahliae, we identified a polyketide synthase gene in V. dahliae, namely VdPKS1. PKS1 is known to involve in the dihydroxynaphthalene melanin synthesis pathway in many fungi. We found that VdPKS1 was required for melanin formation but not for microsclerotial production in E dahliae. The VdPKS1 gene-disruption mutant （vdpksl） formed melanin-deficient albino microsclerotia, which did not affect the fungal colonization in host tissues but significantly reduced the disease severity. Gene transcription analysis in the wild-type and the vdpks1 strains suggested that VdPKS1 gene-disruption influenced the expression of a series of genes involved in ethylene biosynthesis, microsclerotial formation and pathogenesis. Our results suggest that the VdPKS1-mediated melanin synthesis is important for virulence and developmental traits of E dahliae.展开更多
The innate immune responses triggering production of type 1 interferons and inflammatory cytokines constitute a nonspecific innate resistance that eliminates invading pathogens including viruses. The acti- vation of i...The innate immune responses triggering production of type 1 interferons and inflammatory cytokines constitute a nonspecific innate resistance that eliminates invading pathogens including viruses. The acti- vation of innate immune signaling through pattern recognition receptors （PRRs） is by sensing pathogen- associated molecular patterns derived from viruses. According to their distribution within cells, PRRs are classified into three types of receptors： membrane, cytoplasmic, and nuclear. Kaposi＇s sarcoma- associated herpesvirus （I（SHV）, a large DNA virus, replicates in the nucleus. Its genome is protected by capsid proteins during transport in the cytosol. Multiple PRRs are involved in KSHV recognition. To suc- cessfully establish latent infection, KSHV has evolved to manipulate different aspects of the host antiviral innate immune responses. This review presents recent advances in our understanding about the activation of the innate immune signaling in response to infection of KSHV. It also reviews the evasion strate- gies used by KSHV to subvert host innate immune detection for establishing a persistent infection.展开更多
文摘The simulation of the dynamics of viral infections by mathematical equations has been applied successfully to the study of viral infections during antiviral therapy. Standard models applied to viral hepatitis describe the viral load decline in the f irst 2-4 wk of antiviral therapy, but do not adequately simulate the dynamics of viral infection for the following period. The hypothesis of a constant clearance rate of the infected cells provides an unrealistic estimation of the time necessary to reach the control or the clearance of hepatitis B virus (HBV)/ hepatitis C virus (HCV) infection. To overcome the problem, we have developed a new multiphasic model in which the immune system activity is modulated by a negative feedback caused by the infected cells reduction, and alanine aminotransferase kinetics serve as a surrogate marker of infected-cell clearance. By this approach, we can compute the dynamics of infected cells during the whole treatment course, and find a good correlation between the number of infected cells at the end of therapy and the long-term virological response in patients with chronic hepatitis C. The new model successfully describes the HBV infection dynamics far beyond the third month of antiviral therapy under the assumption that the sum of infected and non-infected cells remains roughly constant during therapy, and both target and infected cells concur in the hepatocyte turnover. In clinical practice, these new models will allow the development of simulators of treatment response that will be used as an "automatic pilot" for tailoring antiviral therapy in chronic hepatitis B as well as chronic hepatitis C patients.
文摘Active host-pathogen interactions take place during infection of human immunodeficiency virus type 1 (HIV-1). Outcomes of these interactions determine the efficiency of viral infection and subsequent disease progression. HIV- infected cells respond to viral invasion with various defensive strategies such as innate, cellular and humoral immune antiviral mechanisms. On the other hand, the virus has also developed various offensive tactics to suppress these host cellular responses. Among many of the viral offensive strategies, HIV-1 viral auxiliary proteins (Tat, Rev, Nef, Vif, Vpr and Vpu) play important roles in the host-pathogen interaction and thus have significant impacts on the outcome of HIV infection. One of the best examples is the interaction of Vif with a host cytidine deaminase APOBEC3G. Although specific roles of other auxiliary proteins are not as well described as Vif-APOBEC3G interaction, it is the goal of this brief review to summarize some of the preliminary findings with the hope to stimulate further discussion and investiga- tion in this exhilarating area of research.
文摘The effect of maternal antibodies on the pathogenesis of avian reovirus （ARV） was studied in commercial and specific pathogen free broilers （SPF） using a real-time reverse transcriptase （RT）-polymerase chain reaction （PCR） assay, along with the incidence and severity of morbidity, mortality, and gross lesions. ARV RNA was detected in cloacal swabs in both bird groups from the first day throughout the 21 days experiment. Commercial broiler chickens, which had high maternal antibodies against ARV, showed minimum clinical signs, gross lesions, and lower numbers of birds with viral RNA excretion, whereas specific pathogen free （SPF） broiler chickens, which did not have antibody against ARVs, had 30% mortality, more severe signs, and higher numbers of birds excreting viral RNA. The highest peak of SPF birds excreting viral RNA occurred during the time of maximum mortality. The protective effect of maternal antibody on ARV pathogenesis in broiler chickens correlated with the detection of ARV RNA using the real-time RT-PCR.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB11040500)the National Natural Science Foundation of China(31160351,311060350)Basic Research Projects of Xingjiang Production and Construction Corps(2016AG001)
文摘Verticillium dahliae is a soil-borne phytopathogenic fungus that causes vascular wilt disease in a broad range of hosts. This pathogen survives for many years in soil in the form ofmelanized microsclerotia. To investigate the melanin synthesis in V.. dahliae, we identified a polyketide synthase gene in V. dahliae, namely VdPKS1. PKS1 is known to involve in the dihydroxynaphthalene melanin synthesis pathway in many fungi. We found that VdPKS1 was required for melanin formation but not for microsclerotial production in E dahliae. The VdPKS1 gene-disruption mutant （vdpksl） formed melanin-deficient albino microsclerotia, which did not affect the fungal colonization in host tissues but significantly reduced the disease severity. Gene transcription analysis in the wild-type and the vdpks1 strains suggested that VdPKS1 gene-disruption influenced the expression of a series of genes involved in ethylene biosynthesis, microsclerotial formation and pathogenesis. Our results suggest that the VdPKS1-mediated melanin synthesis is important for virulence and developmental traits of E dahliae.
基金supported by the National Key R&D Program of China (2016YFA0502100)the Natural Science Foundation for Distinguished Young Scholars (81425017)the National Institutes of Health (7R01AI116442) to K.L.
文摘The innate immune responses triggering production of type 1 interferons and inflammatory cytokines constitute a nonspecific innate resistance that eliminates invading pathogens including viruses. The acti- vation of innate immune signaling through pattern recognition receptors （PRRs） is by sensing pathogen- associated molecular patterns derived from viruses. According to their distribution within cells, PRRs are classified into three types of receptors： membrane, cytoplasmic, and nuclear. Kaposi＇s sarcoma- associated herpesvirus （I（SHV）, a large DNA virus, replicates in the nucleus. Its genome is protected by capsid proteins during transport in the cytosol. Multiple PRRs are involved in KSHV recognition. To suc- cessfully establish latent infection, KSHV has evolved to manipulate different aspects of the host antiviral innate immune responses. This review presents recent advances in our understanding about the activation of the innate immune signaling in response to infection of KSHV. It also reviews the evasion strate- gies used by KSHV to subvert host innate immune detection for establishing a persistent infection.
