scholarly journals Japanese Encephalitis Virus Generated Neurovirulence, Antigenicity, and Host Immune Responses

ISRN Virology ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-24 ◽  
Author(s):  
Ravi Kant Upadhyay
Keyword(s):  
Immune Responses ◽  
Clinical Care ◽  
Active Immunization ◽  
Target Cells ◽  
Natural Immunity ◽  
Class I Mhc ◽  
Host Immune Responses ◽  
The Central Nervous System ◽  
Behavioral Impairments ◽  
Global Eradication

In response to a JE virus attack, infected body cells start secretion of different cytokines and activate innate immune response. Virus starts neuronal invasion by entering into nerve cells and inflecting the central nervous system. It avoids exposure of body’s natural immunity and generates neurotrophic effects. Virus causes acute susceptibility to CNS and establishes encephalitis syndrome that results in very high fatality in children. In survivors, JEV inhibits the growth and proliferation of NCPs and imposes permanent neuronal disorders like cognitive, motor, and behavioral impairments. However, body cells start TCR mediated interactions, to recognize viral antigens with class I MHC complex on specific target cells, and operate mass killing of virus infected cells by increased CTL activity. Thus, both cell mediated and antibody interactions plays a central role in protection against JEV. In the present review article virus generated neurovirulence, antigenicity, and host immune responses are described in detail. More emphasis is given on diagnosis, clinical care, and active immunization with well-designed potential antiflavivirus vaccines. Further, for achieving an elite success against JEV, global eradication strategies are to be needed for making vaccination program more responsible and effective in endemic areas.

scholarly journals Viral and Cellular Determinants of the Hepatitis C Virus Envelope-Heparan SulfateInteraction

2006 ◽  
Vol 80 (21) ◽  
pp. 10579-10590 ◽  
Author(s):  
Heidi Barth ◽  
Eva K. Schnober ◽  
Fuming Zhang ◽  
Robert J. Linhardt ◽  
Erik Depla ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Immune Responses ◽  
Viral Infection ◽  
Viral Envelope ◽  
Model Systems ◽  
Target Cells ◽  
Virus Envelope ◽  
Viral Attachment ◽  
Host Immune Responses

ABSTRACT Cellular binding and entry of hepatitis C virus (HCV) are the first steps of viral infection and represent a major target for antiviral antibodies and novel therapeutic strategies. We have recently demonstrated that heparan sulfate (HS) plays a key role in the binding of HCV envelope glycoprotein E2 to target cells (Barth et al., J. Biol. Chem. 278:41003-41012, 2003). In this study, we characterized the HCV-HS interaction and analyzed its inhibition by antiviral host immune responses. Using recombinant envelope glycoproteins, virus-like particles, and HCV pseudoparticles as model systems for the early steps of viral infection, we mapped viral and cellular determinants of HCV-HS interaction. HCV-HS binding required a specific HS structure that included N-sulfo groups and a minimum of 10 to 14 saccharide subunits. HCV envelope binding to HS was mediated by four viral epitopes overlapping the E2 hypervariable region 1 and E2-CD81 binding domains. In functional studies using HCV pseudoparticles, we demonstrate that HCV binding and entry are specifically inhibited by highly sulfated HS. Finally, HCV-HS binding was markedly inhibited by antiviral antibodies derived from HCV-infected individuals. In conclusion, our results demonstrate that binding of the viral envelope to a specific HS configuration represents an important step for the initiation of viral infection and is a target of antiviral host immune responses in vivo. Mapping of viral and cellular determinants of HCV-HS interaction sets the stage for the development of novel HS-based antiviral strategies targeting viral attachment and entry.

scholarly journals Distinct conformational states of SARS-CoV-2 spike protein

Science ◽  
2020 ◽  
pp. eabd4251 ◽  
Author(s):  
Yongfei Cai ◽  
Jun Zhang ◽  
Tianshu Xiao ◽  
Hanqin Peng ◽  
Sarah M. Sterling ◽  
...  
Keyword(s):  
Immune Responses ◽  
Fusion Peptide ◽  
Intervention Strategies ◽  
Spike Protein ◽  
Target Cells ◽  
Spontaneous Transition ◽  
S Protein ◽  
Host Immune Responses ◽  
Binding Domains ◽  
External Conditions

Intervention strategies are urgently needed to control the SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) pandemic. The trimeric viral spike (S) protein catalyzes fusion between viral and target cell membranes to initiate infection. Here we report two cryo-EM structures, derived from a preparation of the full-length S protein, representing its prefusion (2.9Å resolution) and postfusion (3.0Å resolution) conformations, respectively. The spontaneous transition to the postfusion state is independent of target cells. The prefusion trimer has three receptor-binding domains clamped down by a segment adjacent to the fusion peptide. The postfusion structure is strategically decorated by N-linked glycans, suggesting possible protective roles against host immune responses and harsh external conditions. These findings advance our understanding of SARS-CoV-2 entry and may guide development of vaccines and therapeutics.

scholarly journals Distinct conformational states of SARS-CoV-2 spike protein

2020 ◽  
Author(s):  
Yongfei Cai ◽  
Jun Zhang ◽  
Tianshu Xiao ◽  
Hanqin Peng ◽  
Sarah M. Sterling ◽  
...  
Keyword(s):  
Immune Responses ◽  
Structural Transition ◽  
Intervention Strategies ◽  
Target Cells ◽  
S Protein ◽  
Host Immune Responses ◽  
Mild Conditions ◽  
Binding Domains ◽  
External Conditions ◽  
Packed Structure

AbstractThe ongoing SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) pandemic has created urgent needs for intervention strategies to control the crisis. The spike (S) protein of the virus forms a trimer and catalyzes fusion between viral and target cell membranes - the first key step of viral infection. Here we report two cryo-EM structures, both derived from a single preparation of the full-length S protein, representing the prefusion (3.1Å resolution) and postfusion (3.3Å resolution) conformations, respectively. The spontaneous structural transition to the postfusion state under mild conditions is independent of target cells. The prefusion trimer forms a tightly packed structure with three receptor-binding domains clamped down by a segment adjacent to the fusion peptide, significantly different from recently published structures of a stabilized S ectodomain trimer. The postfusion conformation is a rigid tower-like trimer, but decorated by N-linked glycans along its long axis with almost even spacing, suggesting possible involvement in a mechanism protecting the virus from host immune responses and harsh external conditions. These findings advance our understanding of how SARS-CoV-2 enters a host cell and may guide development of vaccines and therapeutics.

scholarly journals Structure, metabolism and biological functions of steryl glycosides in mammals

2020 ◽  
Vol 477 (21) ◽  
pp. 4243-4261
Author(s):  
Michio Shimamura
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Heat Shock ◽  
Animal Models ◽  
Cell Membrane ◽  
Immune Responses ◽  
Biological Functions ◽  
Biophysical Properties ◽  
Host Immune Responses ◽  
The Central Nervous System

Steryl glycosides (SGs) are sterols glycosylated at their 3β-hydroxy group. They are widely distributed in plants, algae, and fungi, but are relatively rare in bacteria and animals. Glycosylation of sterols, resulting in important components of the cell membrane SGs, alters their biophysical properties and confers resistance against stress by freezing or heat shock to cells. Besides, many biological functions in animals have been suggested from the observations of SG administration. Recently, cholesteryl glucosides synthesized via the transglycosidation by glucocerebrosidases (GBAs) were found in the central nervous system of animals. Identification of patients with congenital mutations in GBA genes or availability of respective animal models will enable investigation of the function of such endogenously synthesized cholesteryl glycosides by genetic approaches. In addition, mechanisms of the host immune responses against pathogenic bacterial SGs have partially been resolved. This review is focused on the biological functions of SGs in mammals taking into consideration their therapeutic applications in the future.

Role of convalescent plasma therapy in new Coronavirus disease (nCOVID-19): A review

2020 ◽  
Vol 11 (SPL1) ◽  
pp. 546-549
Author(s):  
Shweta Dadarao Parwe ◽  
Milind Abhimanyu Nisargandha ◽  
Rishikesh Thakre
Keyword(s):  
Clinical Trial ◽  
Immune Responses ◽  
Indian Population ◽  
Preventive Treatment ◽  
The Body ◽  
Therapeutic Antibodies ◽  
Plasma Therapy ◽  
Host Immune Responses ◽  
Transparent Liquid

Hitherto, there is no proper line of treatment for the new (nCOVID19). The development of unique antiviral drugs has taken precedence. Therapeutic antibodies () will be a significantly beneficial agent against nCOVID-19. Here the host immune responses to new discussed in this review provide strategy and further treatment and understanding of clinical interventions against nCOVID-19. Plasma therapy uses the antibodies found in the blood of people recovering (or convalesced) from an infection to treat infected patients. When an infection occurs, the body begins producing proteins specially made to kill the germ, called antibodies. Those antibodies coat specifically plasma in the blood of survivors, the yellow transparent liquid blood portion for months or even years. research assesses plasma use from Convalescent patients of infected with nCOVID-19 as a possible preventive treatment. But it is not yet recommended as a line of treatment, and it is used as a clinical trial in the new in Indian population.

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