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(1) Enterovirus-A71 Infection Activates Human Immune Responses and Induces Pathological Changes in Humanized Mice.[TOP]

Pubmed ID :30429352
Publication Date : //
Since the discovery of enterovirus-A71 (EV-A71) half a century ago, it has caused large-scale outbreaks of hand-foot-and-mouth disease worldwide, in particular in the Asia-Pacific region, causing a great concern of public health and economic burden. Detailed mechanisms on the modulation of immune responses after EV-A71 infection have not been fully known, and the lack of appropriate models hinders the development of promising vaccines and drugs. In the present study, NOD- (NSG) mice with human immune system (humanized mice) at the age of four-week-old were found to be susceptible to a human isolate of EV-A71 infection. After infection, humanized mice displayed limb weakness, which is similar to the clinical features found in some of the EV-A71-infected patients. Histopathological examination indicated the presence of vacuolation, gliosis or meningomyelitis in brain stem and spinal cord, which were accompanied by high viral loads detected in these organs. The numbers of activated human CD4 and CD8 T cells were upregulated after EV-A71 infection and EV-A71-specific human T cell responses were found. Furthermore, the secretion of several proinflammatory cytokines, such as human IFN-γ, IL-8 and IL-17A was elevated in the EV-A71-infected humanized mice. Taken together, our results suggested that the humanized mouse model permits insights into the human immune responses and the pathogenesis of EV-A71 infection, which may provide a platform for the evaluation of anti-EV-A71 drug candidates in the future. Despite causing self-limited hand-food-and-mouth disease in younger children, EV-A71 is consistently associated with severe forms of neurological complications and pulmonary edema. Nevertheless, only limited vaccines and drugs have been developed over the years, which is possibly due to a lack of models that can more accurately recapitulate human specificity, since human is the only natural host for wild type EV-A71 infection. Our humanized mouse model did not only mimic histological symptoms in patients, but also allows us to investigate the function of human immune system during the infection. It was found that human T cell responses were activated, accompanied by an increase in the production of proinflammatory cytokines in EV-A71-infected humanized mice, which might contribute to the exacerbation of disease pathogenesis. Collectively, this model allows us to delineate the modulation of human immune responses during EV-A71 infection and may provide a platform to evaluate anti-EV-A71 drug candidates in the future.

Authors : Ke Yanyan, Liu Wai Nam, Her Zhisheng, Liu Min, Tan Sue Yee, Tan Yong Wah, Chan Xue Ying, Fan Yong, Huang Edwin Kunxiang, Chen Huiyi, Chang Kenneth Tou En, Chan Jerry Kok Yen, Hann Chu Justin Jang, Chen Qingfeng,

(2) Competitive Luminex immunoassays for detection of antibodies to foot-and-mouth disease and vesicular stomatitis viruses in multiple susceptible hosts.[TOP]

Pubmed ID :30363380
Publication Date : //
Foot-and-mouth disease (FMD) and vesicular stomatitis (VS) cause such similar clinical signs and lesions that laboratory tests are required to distinguish between infections caused by each virus. Using mouse anti-foot-and-mouth disease virus (FMDV) 3B monoclonal or polyclonal anti-vesicular stomatitis virus-New Jersey (VSV-NJ) antibodies and recombinant FMDV 3ABC or VSV-NJ glycoprotein (G) antigens coated to MagPlex beads, competitive Luminex immunoassays (cLIAs) were developed for FMDV and VSV-NJ, respectively. The cLIAs successfully detected antibodies to FMDV 3ABC and VSV-NJ G in sera from infected animals. The diagnostic sensitivity and specificity were 93% and 98%, respectively for FMDV and 93% and 95.4%, respectively for VSV-NJ. These cLIAs are potential alternatives for competitive enzyme-linked immunosorbent assays (cELISAs) and provide the opportunity for multiplexing to reduce time and the amount of serum required for testing.

Authors : Nfon Charles, Lusansky Diana, Goolia Melissa, Yang Ming, Hole Kate, McIntyre Leanne,

(3) Virus-like particles of recombinant PCV2b carrying FMDV-VP1 epitopes induce both anti-PCV and anti-FMDV antibody responses.[TOP]

Pubmed ID :30338355
Publication Date : //
Mixed infection of porcine circovirus type 2 (PCV2) and foot-and-mouth disease virus (FMDV) is devastating to swine populations. To develop an effective vaccine that can protect the pigs from the infection of PCV2 and FMDV, we used the neutralizing B cell epitope region (aa 135-160) of FMDV to replace the regions aa 123-151 and aa 169-194 of the PCV2b Cap protein to generate a recombinant protein designated as Capfb. The Capfb protein was expressed in Escherichia coli system and the purified Capfb protein assembled into virus-like particles (VLPs) through dialysis. The ability of the Capfb protein to induce effective immune response against FMDV and PCV2b was tested in mice and guinea pigs. The results showed that the Capfb-VLPs could elicit anti-PCV2b and anti-FMDV antibody response in mice and guinea pigs without inducing antibodies against decoy epitope. Moreover, the Capfb-VLPs could enhance the percentage and activation of B cells in lymph nodes when the mice were stimulated with inactivated FMDV or PCV2b. These data suggested that the Capfb-VLPs could be an efficacious candidate antigen for developing a novel PCV2b-FMDV bivalent vaccine.

Authors : Li Xin, Meng Xiuping, Wang Shengnan, Li Zhiqin, Yang Lei, Tu Liqun, Diao Wenzhen, Yu Cheng, Yu Yongli, Yan Chaoying, Wang Liying,

(4) Immune Modulatory Potential of Anti-idiotype Antibodies as a Surrogate of Foot-and-Mouth Disease Virus Antigen.[TOP]

Pubmed ID :30333183
Publication Date : //
The immunoprophylactic potential of anti-idiotype (anti-id) foot-and-mouth disease (FMD) antigen (Ag) was evaluated in the calves. The idiotype antibodies (Ab1) were produced in experimental goats by injecting inactivated FMD virus. The Fab (fragment antigen binding) of Ab1 was injected into the layer birds to raise anti-id antibodies (Ab2). The Ab2 was purified from egg yolks. The Fab component of Ab2 was emulsified in Montanide (1:1) and used as a surrogate of FMD virus. The immune response to Montanide adjuvanted monovalent and trivalent anti-id FMD virus antigen was determined in mice. The comparative immune potentiation potentials of Montanide adjuvanted trivalent anti-id FMD virus antigen and trivalent FMD vaccine were determined in mice and calves. Montanide adjuvanted monovalent anti-id FMD virus antigens produced mean Ab titers of 78.80%, 81.30%, and 81.20% for serotypes A, Asia 1, and O, respectively, at 45 days postimmunization (p.i.) in mice. Montanide adjuvanted trivalent anti-id FMD Ag in mice produced the highest Ab titer, 81.60%, at day 45 compared to the 77.50% titer measured for Montanide adjuvanted FMD vaccine at day 45 p.i. A slow decrease of 1% to 2% was recorded for the Ab titer of Montanide adjuvanted trivalent anti-id FMD virus antigen in mice at day 60. In calves, the titer corresponding to the immune response seen with Montanide adjuvanted trivalent anti-id FMD virus antigen (80%) was persistent whereas the titer of Montanide adjuvanted FMD vaccine decreased to 74% at day 60 p.i. Anti-id FMD virus antigen induced a strong and persistent immunogenic response in terms of Ab titer compared to the inactivated virus vaccine. Anti-id FMD virus antigen may serve as a surrogate of FMD virus vaccine. Foot-and-mouth disease (FMD) is a contagious viral disease of animals. Multiple serotypes and antigenic variation in the viral genome are probably the factors that reduce control of the disease. Currently, the vaccines employed against FMD use killed virus. The inactivation or killing of the virus makes it less immunogenic and reduces its immunoprophylactic potential. To cope with this situation, the present study was designed, anti-idiotype FMD virus antigen was prepared, and the immunogenic potential of the antigen was compared to that of commercial killed-virus vaccines. The overall results showed that a persistent and strong immune response occurred with anti-idiotype FMD virus antigen. Thus, anti-idiotype FMD virus antigen may serve as a potential surrogate of FMD virus vaccines.

Authors : Naveed Ahsan, Rahman Sajjad Ur, Arshad Muhammad Imran, Aslam Bilal,

(5) Generation and characterisation of recombinant FMDV antibodies: Applications for advancing diagnostic and laboratory assays.[TOP]

Pubmed ID :30114227
Publication Date : //
Foot-and-mouth disease (FMD) affects economically important livestock and is one of the most contagious viral diseases. The most commonly used FMD diagnostic assay is a sandwich ELISA. However, the main disadvantage of this ELISA is that it requires anti-FMD virus (FMDV) serotype-specific antibodies raised in small animals. This problem can be, in part, overcome by using anti-FMDV monoclonal antibodies (MAbs) as detecting reagents. However, the long-term use of MAbs may be problematic and they may need to be replaced. Here we have constructed chimeric antibodies (mouse/rabbit D9) and Fabs (fragment antigen-binding) (mouse/cattle D9) using the Fv (fragment variable) regions of a mouse MAb, D9 (MAb D9), which recognises type O FMDV. The mouse/rabbit D9 chimeric antibody retained the FMDV serotype-specificity of MAb D9 and performed well in a FMDV detection ELISA as well as in routine laboratory assays. Cryo-electron microscopy analysis confirmed engagement with antigenic site 1 and peptide competition studies identified the aspartic acid at residue VP1 147 as a novel component of the D9 epitope. This chimeric expression approach is a simple but effective way to preserve valuable FMDV antibodies, and has the potential for unlimited generation of antibodies and antibody fragments in recombinant systems with the concomitant positive impacts on the 3Rs (Replacement, Reduction and Refinement) principles.

Authors : Shimmon Gareth, Kotecha Abhay, Ren Jingshan, Asfor Amin S, Newman Joseph, Berryman Stephen, Cottam Eleanor M, Gold Sarah, Tuthill Toby J, King Donald P, Brocchi Emiliana, King Andrew M Q, Owens Ray, Fry Elizabeth E, Stuart David I, Burman Alison, Jackson Terry,

(6) Dissecting complicated viral spreading of enterovirus 71 using in situ bioorthogonal fluorescent labeling.[TOP]

Pubmed ID :30086449
Publication Date : //
Enterovirus 71 (EV71), the major pathogen of hand-foot-and-mouth disease (HFDM), can cause severe neurological and respiratory manifestations in young children. Viral spread route and tissue tropism are key factors contributing to different pathogenicity of EV71, however it remains a challenge to dynamically visualize EV71 infection in vivo. The present study applies an in situ bioorthogonal fluorescent labeling strategy to track clinically isolated EV71 strains with different pathogenicity in neonatal mice. The results show that the in situ labeling strategy effectively captures EV71 viruses through in vivo bioorthogonal reaction in multiple infected organs without interfering viral spread and tissue tropism. More importantly, the in situ labeling reveals different viral dynamics, dissemination, and tissue tropism of severe case EV71 (SC-EV71) and mild case EV71 (MC-EV71), consistent with their different pathogenicity in HFDM patients. Compared with MC-EV71, SC-EV71 not only enters the blood circulation and spreads out more quickly, but also shows more significant neuronal and respiratory tropism, which certainly contribute severe neurological complications and clinical manifestations in the patient. Hence, the in situ bioorthogonal fluorescent labeling is a plausible strategy to dissect complicated process of EV71 viral spread in the early stage of infection, thereby offering great opportunities to understand its pathogenesis and develop anti-viral drugs.

Authors : Pan Hong, Yao Xiangjie, Chen Weihua, Wang Fangfang, He Huamei, Liu Lanlan, He Yaqing, Chen Jinquan, Jiang Puzi, Zhang Renli, Ma Yifan, Cai Lintao,

(7) Establishment and characterization of an oral gerbil model for a non-mouse-adapted enterovirus 71 strain.[TOP]

Pubmed ID :30030018
Publication Date : //
Enterovirus 71 (EV71) is one of the major pathogens causing hand, foot, and mouth disease (HFMD) with neurological and systemic complications worldwide, and it is mostly discovered in infants and young children. It is of great significance to establish suitable animal models of EV71 infection on research of distribution and pathogenesis of the virus. In this study, we established a successful infection of a non-mouse-adapted isolate of EV71 via oral route in 7-day-old Mongolian gerbil (Meriones unguiculatus), all of which were paralyzed and died within 10 days post infection. Analysis of virus loads in twelve tissues showed that virus was first detected in intestine, blood, heart, lung, and muscle one day post-infection, and then in the rest of the tissues/organs within the next few days, among which thymus, spleen, spinal cord and muscles had the highest virus titer at 5 days post infection. Pathological examination showed that severe necrosis was observed in skeletal muscle and spinal cord, and edema was observed in both heart and lung. Comparisons of host gene expression of various tissues from infected and non-infected gerbils revealed a general up-regulation of genes related to anti-viral response and a viral receptor gene (sialic acid-linked glycans), as well as a tissue(gut)-specific up-regulation of genes related to neuronal communication. Collectively, our results showed that EV71 could induce severe neurological complications as well as massive tissue damage all over the body, which indicates that oral infection of 7-day gerbils can be a suitable animal model to study the infection of EV71 in human.

Authors : Li Ci-Xiu, Zhang Bing, Feng Yan, Xu Chang-Ping, Jiang Jian-Min, Lu Yi-Yu,

(8) Induction of a high-titered antibody response using HIV gag-EV71 VP1-based virus-like particles with the capacity to protect newborn mice challenged with a lethal dose of enterovirus 71.[TOP]

Pubmed ID :29582164
Publication Date : //
Enterovirus 71 (EV71) is the most frequently detected causative agent in hand, foot, and mouth disease (HFMD) and is a serious threat to public health in the Asia-Pacific region. Many EV71 vaccines are under development worldwide, and although both inactivated virus vaccines and virus-like particles (VLPs) are considered to be effective, the main focus has been on inactivated EV71vaccines. There have been very few studies on EV71 VLPs. In this study, using a strategy based on HIV gag VLPs, we constructed a gag-VP1 fusion gene to generate a recombinant baculovirus expressing the EV71 structural protein VP1 together with gag, which was then used to infect TN5 cells to form VLPs. The VLPs were characterized using transmission electron microscopy, electrophoresis and staining with Coomassie blue, and Western blotting. Mice immunized with gag-VP1 VLPs showed strong humoral and cellular immune responses. Finally, immunization of female mice with gag-VP1 VLPs provided effective protection of their newborn offspring against challenge with a lethal dose EV71. These results demonstrate a successful approach for producing EV71 VP1 VLPs based on the ability of HIV gag to self-assemble, thus providing a good foundation for producing high-titered anti-EV71 antibody by immunization with VLP-based gag EV71 VP1 protein.

Authors : Wang Xi, Dong Ke, Long Min, Lin Fang, Gao Zhaowei, Wang Lin, Zhang Zhe, Chen Xi, Dai Ying, Wang Huiping, Zhang Huizhong,

(9) A virus-like particle vaccine protects mice against coxsackievirus A10 lethal infection.[TOP]

Pubmed ID :29470994
Publication Date : //
Coxsackievirus A10 (CVA10) has emerged worldwide as one of the main pathogens of hand, foot, and mouth disease (HFMD) in recent years. However, there is currently no commercial vaccine available to prevent CVA10 infection. Here we report the development of a recombinant virus-like particle (VLP) based candidate vaccine for CVA10. Co-expression of the capsid protein precursor P1 and the protease 3CD of CVA10 in Pichia pastoris resulted in cleavage of P1 into three capsid subunit proteins VP0, VP1, and VP3. These three subunit proteins co-assembled into CVA10 VLPs, which were visualized as spherical particles with a diameter of ∼30 nm under electron microscope. Immunization studies showed that CVA10 VLP could efficiently induce antigen-specific serum antibodies in mice. The anti-VLP sera were able to potently neutralize homologous and heterologous CVA10 strains. Importantly, passively transferred anti-VLP sera fully protected recipient neonatal mice from lethal CVA10 infection. In addition, neonatal mice born to the VLP-immunized dams were also completely protected from CVA10 lethal challenge. Collectively, these data show that CVA10 VLP represents a promising CVA10 vaccine candidate.

Authors : Zhou Yu, Zhang Chao, Liu Qingwei, Gong Sitang, Geng Lanlan, Huang Zhong,

(10) Prohibitin plays a critical role in Enterovirus 71 neuropathogenesis.[TOP]

Pubmed ID :29324904
Publication Date : //
A close relative of poliovirus, enterovirus 71 (EV71) is regarded as an important neurotropic virus of serious public health concern. EV71 causes Hand, Foot and Mouth Disease and has been associated with neurological complications in young children. Our limited understanding of the mechanisms involved in its neuropathogenesis has hampered the development of effective therapeutic options. Here, using a two-dimensional proteomics approach combined with mass spectrometry, we have identified a unique panel of host proteins that were differentially and dynamically modulated during EV71 infection of motor-neuron NSC-34 cells, which are found at the neuromuscular junctions where EV71 is believed to enter the central nervous system. Meta-analysis with previously published proteomics studies in neuroblastoma or muscle cell lines revealed minimal overlapping which suggests unique host-pathogen interactions in NSC-34 cells. Among the candidate proteins, we focused our attention on prohibitin (PHB), a protein that is involved in multiple cellular functions and the target of anti-cancer drug Rocaglamide (Roc-A). We demonstrated that cell surface-expressed PHB is involved in EV71 entry into neuronal cells specifically, while membrane-bound mitochondrial PHB associates with the virus replication complex and facilitates viral replication. Furthermore, Roc-A treatment of EV71-infected neuronal cells reduced significantly virus yields. However, the inhibitory effect of Roc-A on PHB in NSC-34 cells was not through blocking the CRAF/MEK/ERK pathway as previously reported. Instead, Roc-A treated NSC-34 cells had lower mitochondria-associated PHB and lower ATP levels that correlated with impaired mitochondria integrity. In vivo, EV71-infected mice treated with Roc-A survived longer than the vehicle-treated animals and had significantly lower virus loads in their spinal cord and brain, whereas virus titers in their limb muscles were comparable to controls. Together, this study uncovers PHB as the first host factor that is specifically involved in EV71 neuropathogenesis and a potential drug target to limit neurological complications.

Authors : Too Issac Horng Khit, Bonne Isabelle, Tan Eng Lee, Chu Justin Jang Hann, Alonso Sylvie,