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Japanese Encephalitis Virus Generated Neurovirulence, Antigenicity, and Host Immune Responses  [PDF]
Ravi Kant Upadhyay
ISRN Virology , 2013, DOI: 10.5402/2013/830396
Abstract: 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. 1. Introduction 1.1. Japanese Encephalitis Virus Japanese encephalitis virus (JEV) is an enveloped positive single stranded RNA virus that belongs to genus Flavivirus in the family Flaviviridae. JE is one of the most important endemic diseases that exists in Eastern Asia and Southeastern Asia including India, Nepal, Japan, China, Korea, Thailand, Indonesia, Malaysia, Vietnam, Taiwan, and the Philippines. Recently disease has shown its presence in Continental Australia and New Zealand. JE is a major public health problem, which causes high morbidity and mortality in pediatric groups. It is caused by a dreadful mosquito-borne virus (arbovirus) which is transmitted to human by mosquito, that is, Culex tritaeniorhynchus and Culex vishnui throughout rural areas of Asia. The natural cycle of Japanese encephalitis (JE) virus in endemic areas involves presence of water birds and Culex mosquitoes, particularly Culex tritaeniorhynchus, with pigs being also involved as an amplifying host and providing a link to humans through their proximity to housing. These play important role in amplification, dispersal, and epidemiology of JEV [1]. Transmission of JEV is seasonal, which increases with the increase in number of culicine mosquitoes after more
Study on the determinants of suckling mice neurovirulence of dengue 2 virus
Wei Zhao,Baochang Fan,Zhijun Hu,Suiping Chen,Pengcheng Wang,Xitong Yuan,Xiaoyu Li,Man Yu,Ede Qin,Peiying Yang
Science China Life Sciences , 2003, DOI: 10.1007/BF03182689
Abstract: pDVWS501 was a genomic-length cDNA clone of dengue 2 virus, through which infectious virus (MON501) could be rescued. MON501 was neurovirulent in mice, whose E residues 62 and 203 were Lys and Asn, respectively. Two genomic-length cDNA clones (TB62 and TB203) were constructed by pointed mutation of pDVWS501 with OL-PCR, E62 of TB62 and E203 of TB203 were converted to Glu and Asp, respectively. RNA transcripts of pDVWS501, TB62 and TB203 were producedin vitro and electroporated into BHK-21 cells. The cultures were collected after 7 days and used as inoculum to infect C6/36 cells. The existence of rescued dengue viruses in the culture was proved by RT-PCR, and the typical cytopathic effect (CPE) of C6/36 caused by dengue virus emerged after 2–5 days’ inoculation. Sequence analysis further confirmed the existence of recovered and recombinant DEN2 viruses, whose 5′ termini had an additional non-virus nucleotides “G”, while the 3′ terminal sequences remained the same as natural. The neurovirulence of three viruses was evaluated in 1-day-old mice by the intracerebral route with 105-102 TCID50. Compared with MON501 group, the number of infected mice with the signs of encephalitis in HFT62 and HFT203 groups was less, and the surviving time was longer. The properties of these mutants demonstrated that E62 and E203 are determinants of suckling mice neurovirulence.
Mathematical modeling of antigenicity for HIV dynamics  [PDF]
Fran?ois Dubois,Hervé Le Meur,Claude Reiss
Mathematics , 2008,
Abstract: This contribution is devoted to a new model of HIV multiplication motivated by the patent of one of the authors. We take into account the antigenic diversity through what we define "antigenicity", whether of the virus or of the adapted lymphocytes. We model the interaction of the immune system and the viral strains by two processes. On the one hand, the presence of a given viral quasi-species generates antigenically adapted lymphocytes. On the other hand, the lymphocytes kill only viruses for which they have been designed. We consider also the mutation and multiplication of the virus. An original infection term is derived. So as to compare our system of differential equations with well-known models, we study some of them and compare their predictions to ours in the reduced case of only one antigenicity. In this particular case, our model does not yield any major qualitative difference. We prove mathematically that, in this case, our model is biologically consistent (positive fields) and has a unique continuous solution for long time evolution. In conclusion, this model improves the ability to simulate more advanced phases of the disease.
A Molecularly Cloned, Live-Attenuated Japanese Encephalitis Vaccine SA14-14-2 Virus: A Conserved Single Amino Acid in the ij Hairpin of the Viral E Glycoprotein Determines Neurovirulence in Mice  [PDF]
Sang-Im Yun equal contributor,Byung-Hak Song equal contributor,Jin-Kyoung Kim,Gil-Nam Yun,Eun-Young Lee,Long Li,Richard J. Kuhn,Michael G. Rossmann,John D. Morrey,Young-Min Lee
PLOS Pathogens , 2014, DOI: doi/10.1371/journal.ppat.1004290
Abstract: Japanese encephalitis virus (JEV), a mosquito-borne flavivirus that causes fatal neurological disease in humans, is one of the most important emerging pathogens of public health significance. JEV represents the JE serogroup, which also includes West Nile, Murray Valley encephalitis, and St. Louis encephalitis viruses. Within this serogroup, JEV is a vaccine-preventable pathogen, but the molecular basis of its neurovirulence remains unknown. Here, we constructed an infectious cDNA of the most widely used live-attenuated JE vaccine, SA14-14-2, and rescued from the cDNA a molecularly cloned virus, SA14-14-2MCV, which displayed in vitro growth properties and in vivo attenuation phenotypes identical to those of its parent, SA14-14-2. To elucidate the molecular mechanism of neurovirulence, we selected three independent, highly neurovirulent variants (LD50, <1.5 PFU) from SA14-14-2MCV (LD50, >1.5×105 PFU) by serial intracerebral passage in mice. Complete genome sequence comparison revealed a total of eight point mutations, with a common single G1708→A substitution replacing a Gly with Glu at position 244 of the viral E glycoprotein. Using our infectious SA14-14-2 cDNA technology, we showed that this single Gly-to-Glu change at E-244 is sufficient to confer lethal neurovirulence in mice, including rapid development of viral spread and tissue inflammation in the central nervous system. Comprehensive site-directed mutagenesis of E-244, coupled with homology-based structure modeling, demonstrated a novel essential regulatory role in JEV neurovirulence for E-244, within the ij hairpin of the E dimerization domain. In both mouse and human neuronal cells, we further showed that the E-244 mutation altered JEV infectivity in vitro, in direct correlation with the level of neurovirulence in vivo, but had no significant impact on viral RNA replication. Our results provide a crucial step toward developing novel therapeutic and preventive strategies against JEV and possibly other encephalitic flaviviruses.
Antigenicity  [cached]
Rao S
Indian Journal of Ophthalmology , 1972,
T.R. Neyestani,M. Djalali,M. Iezeshki
Iranian Journal Of Allergy, Asthma and Immunology , 2000,
Abstract: Antigenicity of proteins found in cow's milk is age dependent. This is primarily due to infants possessing a more permeable intestinal wall than that in adults. Thus infants may acquire cow's milk allergy during their first year of life. While milk antigen specific IgE may cause allergy in susceptible subjects, there is some evidence indicating that milk antigen specific IgG may play some role in chronic disease development. The puropose of this study was to determine the antigenicity of cow's milk proteins in two animal models and to recommend the more sensitivie one, as an evaluation tool, to assess the antigenicity of a poteintial hypoallergenic formula. A crude extract of cow's milk was injected either to young male rabbits or BALB/C mice in four doses. Pure standard proteins of cow's milk were also injected to separate groups of animals to use their anti sera in later stages. The polyclonal pooled serum was then used to evaluate the antigenicity of the extract by indirect enzyme-linked immunossorbeni assay (LEISA). and Western blotting. Both the rabbit and BALB/C murine mode! demonstrated strong ELISA titres against casein and BSA proteins. However, the rabbit model also had a high antibody response against beta-lactoglobulin (/Mg). The lowest antibody response was found against alpha-kictalbumin ( -la) in both animal models and no response against immunoglobulins (Igs) in either model. In Western blotting, rabbit antiserum showed four bands ( -la, /Mg, caseins and BSA) compared to two bands (caseins and BSA) for mouse antiserum. Considering the allergenicity of these proteins in genetically prone subjects, it may be wise to exclude food sources of caseins as well as major whey proteins (BSA), from the diet of infants with a family history of atopy during the first year of life. The rabbit hyperimmunization model was more sensitive than the murine mode! in detecting antibodies against milk proteins. Thus, the rabbii model should be employed when evaluating the antigenicity of a hydro lysate formula.
Je narrant et je narré dans le discours autobiographique
Carmen Onel
Studii si Cercetari Filologice : Seria Limbi Romanice , 2007,
Abstract: Je narrant et je narré se manifestent comme actants du récit autobiographique. D’habitude, le je narrant est employé avec le présent du verbe, tandis que le je narré est employé avec le passé. Il y en a des cas où le je narré est employé avec des verbes au futur, dans un discours prédictif, qui annonce au lecteur ce que l’auteur fera après sa mort Le contexte est très important dans l’interprétation des deux instances
Improving Antigenicity of the Recombinant Hepatitis C Virus Core Protein via Random Mutagenesis
Chen-Ji Huang,Hwei-Ling Peng,Chih-Yu Cheng
Journal of Biomedicine and Biotechnology , 2011, DOI: 10.1155/2011/359042
Abstract: In order to enhance the sensitivity of diagnosis, a recombinant clone containing domain I of HCV core (amino acid residues 1 to 123) was subjected to random mutagenesis. Five mutants with higher sensitivity were obtained by colony screening of 616 mutants using reverse ELISA. Sequence analysis of these mutants revealed alterations focusing on W84, P95, P110, or V129. The inclusion bodies of these recombinant proteins overexpressed in E. coli BL21(DE3) were subsequently dissolved using 6 M urea and then refolded by stepwise dialysis. Compared to the unfolded wild-type antigen, the refolded M3b antigen (W84S, P110S and V129L) exhibited an increase of 66% antigenicity with binding capacity of 0.96 and affinity of 113 μM−1. Moreover, the 33% decrease of the production demand suggests that M3b is a potential substitute for anti-HCV antibody detection.
Determinants of antigenicity and specificity in immune response for protein sequences
Yulong Wang, Wenjun Wu, Nicolas N Negre, Kevin P White, Cheng Li, Parantu K Shah
BMC Bioinformatics , 2011, DOI: 10.1186/1471-2105-12-251
Abstract: Our analysis using protein properties suggested that sequence composition combined with evolutionary information and predicted secondary structure, as well as solvent accessibility is sufficient to predict successful peptide epitopes. The antigenicity and the specificity in immune response were also found to depend on the epitope length. We trained the B-Cell Epitope Oracle (BEOracle), a support vector machine (SVM) classifier, for the identification of continuous B-Cell epitopes with these protein properties as learning features. The BEOracle achieved an F1-measure of 81.37% on a large validation set. The BEOracle classifier outperformed the classical methods based on propensity and sophisticated methods like BCPred and Bepipred for B-Cell epitope prediction. The BEOracle classifier also identified peptides for the ChIP-grade antibodies from the modENCODE/ENCODE projects with 96.88% accuracy. High BEOracle score for peptides showed some correlation with the antibody intensity on Immunofluorescence studies done on fly embryos. Finally, a second SVM classifier, the B-Cell Region Oracle (BROracle) was trained with the BEOracle scores as features to predict the performance of antibodies generated with large protein regions with high accuracy. The BROracle classifier achieved accuracies of 75.26-63.88% on a validation set with immunofluorescence, immunohistochemistry, protein arrays and western blot results from Protein Atlas database.Together our results suggest that antigenicity is a local property of the protein sequences and that protein sequence properties of composition, secondary structure, solvent accessibility and evolutionary conservation are the determinants of antigenicity and specificity in immune response. Moreover, specificity in immune response could also be accurately predicted for large protein regions without the knowledge of the protein tertiary structure or the presence of discontinuous epitopes. The dataset prepared in this work and the classifier
Antigenicity and Immunogenicity of Plasmodium vivax Merozoite Surface Protein-3  [PDF]
Amanda R. Bitencourt, Elaine C. Vicentin, Maria C. Jimenez, Ricardo Ricci, Juliana A. Leite, Fabio T. Costa, Luis C. Ferreira, Bruce Russell, Fran?ois Nosten, Laurent Rénia, Mary R. Galinski, John W. Barnwell, Mauricio M. Rodrigues, Irene S. Soares
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0056061
Abstract: A recent clinical trial in African children demonstrated the potential utility of merozoite surface protein (MSP)-3 as a vaccine against Plasmodium falciparum malaria. The present study evaluated the use of Plasmodium vivax MSP-3 (PvMSP-3) as a target antigen in vaccine formulations against malaria caused by P. vivax. Recombinant proteins representing MSP-3α and MSP-3β of P. vivax were expressed as soluble histidine-tagged bacterial fusions. Antigenicity during natural infection was evaluated by detecting specific antibodies using sera from individuals living in endemic areas of Brazil. A large proportion of infected individuals presented IgG antibodies to PvMSP-3α (68.2%) and at least 1 recombinant protein representing PvMSP-3β (79.1%). In spite of the large responder frequency, reactivity to both antigens was significantly lower than was observed for the immunodominant epitope present on the 19-kDa C-terminal region of PvMSP-1. Immunogenicity of the recombinant proteins was studied in mice in the absence or presence of different adjuvant formulations. PvMSP-3β, but not PvMSP-3α, induced a TLR4-independent humoral immune response in the absence of any adjuvant formulation. The immunogenicity of the recombinant antigens were also tested in formulations containing different adjuvants (Alum, Salmonella enterica flagellin, CpG, Quil A,TiterMax? and incomplete Freunds adjuvant) and combinations of two adjuvants (Alum plus flagellin, and CpG plus flagellin). Recombinant PvMSP-3α and PvMSP-3β elicited higher antibody titers capable of recognizing P. vivax-infected erythrocytes harvested from malaria patients. Our results confirm that P. vivax MSP-3 antigens are immunogenic during natural infection, and the corresponding recombinant proteins may be useful in elucidating their vaccine potential.
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