Epitopes Of Envelope Protein Research Articles

Predicting immune response targets in orthoflaviviruses through sequence homology and computational analysis.

Flaviviruses cause severe encephalitic or hemorrhagic diseases in humans. Its members, Kyasanur forest disease virus (KFDV) and Alkhumra hemorrhagic fever virus (ALKV), cause hemorrhagic fever and are prevalent in India and Saudi Arabia, respectively, while the tick-borne encephalitis virus (TBEV) causes a dangerous encephalitic infection in Europe and Asia. However, little information is available about the targets of immune responses for these deadly viruses. Here, we predict potential antigenic peptide epitopes of viral envelope protein for inducing a cell-mediated and humoral immune response. Using the Immune Epitope Database and Analysis Resource (IEDB-AR), we identified 13 MHC-I and two MHC-II dominant conserved epitopes in KFDV and ALKV and six MHC-I and three MHC-II epitopes in TBEV envelope proteins. Parallelly, we also predicted B-cell linear and discontinuous envelope protein epitopes for these viruses. Interestingly, the epitopes are conserved in all three viral envelope proteins. Further, the discontinuous epitopes are structurally compared with the available DENV, ZIKV, WNV, TBEV, and LIV envelope protein antibody structures. Overall structural comparison analyses highlight (i) lateral ridge epitope in the ED-III domain of E protein, and (ii) envelope dimer epitope (EDE) could be targeted for developing potent vaccine candidates as well as therapeutic antibody production. Moreover, existing structural and biochemical functions of the same epitopes in homologous viruses are predicted to have a reduced antibody-dependent enhancement (ADE) effect on flaviviral infection.

Prediction of B cell epitopes in envelope protein of dengue virus using immunoinformatics approach

Prediction of B cell epitopes in envelope protein of dengue virus using immunoinformatics approach

Designing Multi‐Epitope Subunit Vaccine Candidate for Zika Virus Utilizing In silico Tools

Background: The arboviruses Zika virus (ZIKV) is a pathogen that threatens human health. Scientists have warned that a single mutation in the mosquito-borne ZIKV could spark another major outbreak of the disease in humans. Therefore, designing a suitable vaccine for this virus seems necessary. This study aimed to predict the protective epitopes of envelope protein from the Zika virus with bioinformatics methods for multi-epitope vaccine development. Materials and Methods: Computational studies including the identification of potential B-cell and T-cell epitopes were used. For generating a multi-epitopic vaccine construct (MEVC), selected epitopes are connected by suitable linkers. To enhance protein immunogenicity, Maltosebound protein was added to the MEVC after the prediction and refinement of the 3D structure of the designed vaccine. The binding mode of the MEVC with toll-like receptor was investigated by molecular docking technique. Finally, molecular dynamics and in silico cloning were performed for the designed vaccine. Results: This study showed that this recombinant vaccine is nontoxic, nonallergenic, and thermostable and elicits immune responses against the Zika virus. Conclusion: The computational data suggest that the MEVC has appropriate characteristics and a high-quality structure.

A Novel Recombinant Virus-Like Particles Displaying B and T Cell Epitopes of Japanese Encephalitis Virus Offers Protective Immunity in Mice and Guinea Pigs.

Virus-like particles (VLPs) are non-replicative vectors for the delivery of heterologous epitopes and are considered one of the most potent inducers of cellular and humoral immune responses in mice and guinea pigs. In the present study, VLP-JEVe was constructed by the insertion of six Japanese encephalitis virus (JEV) envelope protein epitopes into different surface loop regions of PPV VP2 by the substitution of specific amino acid sequences without altering the assembly of the virus; subsequently, the protective efficacy of this VLP-JEVe was evaluated against JEV challenge in mice and guinea pigs. Mice immunized with the VLP-JEVe antigen developed high titers of neutralizing antibodies and 100% protection against lethal JEV challenge. The neutralizing and hemagglutination inhibition (HI) antibody responses were also induced in guinea pigs vaccinated with VLP-JEVe. In addition, immunization with VLP-JEVe in mice induced effective neutralizing antibodies and protective immunity against PPV (porcine parvovirus) challenge in guinea pigs. These studies suggest that VLP-JEVe produced as described here could be a potential candidate for vaccine development.

GENERATING RESPONSES IMMUNE IN CELLULAR AND HUMORAL TREATMENT WITH EPITOPE SPIKE, EPITOPE ENVELOPE PROTEIN, AND EPITOPE MEMBRANE PROTEIN SARS-COV-2, HONEY, SAUSSUREA LAPPA, AND NIGELLA SATIVA.

Background:Covid-19 has become pandemic in the World, including Indonesia. Our last study showed that HSF could serve as an immunomodulator. Using the exact search, we found that the most immuno-dominant SARS-COV2 epitope, namely A spike protein epitope, B envelope protein epitope, and C membrane protein epitope, we concise to be HFMaterials and Methods:We used to post only control design study and mice as an animal model. The research divided mice into four groups, and the first group as control received PBS as a placebo. The second, three, and last four groups gave HF, HSN, and HFHSN (combine HF and HSN). All of the regiment enters the mouth with a special sonde to reach the gastrointestinal organ. We gave HF every week three times and HSN once a day. After administration regiments for a long three weeks, we sacrificed the mice. We evaluated cellular immune responses that are Th-2, Th-17, and NK cells. We check for humoral immune response, TGF-β,IL-17A, IL-4, IgG,IL-4, β-defensin, and s-IgA.Results:Highest profile cellular immunity HF, HSN, and HFHSN were NK cell, Th-2 and Th-17, and the last NK cell, respectively. After that which in humoral immunity, the domination response IgG and IL-4 were HF. But HSN and HFHSN dominated for s-IgA and β-defensin production. By using the study Bio-Informatica, we found HF.Conclusion:If the results of this study are continued to the clinical trial level, it is necessary to recommend additional markers such as CTL (s-IgA and β-defensin in lung tissue)and CPE assay.

GENERATING RESPONSES IMMUNE IN CELLULAR AND HUMORAL TREATMENT WITH EPITOPE SPIKE, EPITOPE ENVELOPE PROTEIN, AND EPITOPE MEMBRANE PROTEIN SARS-COV-2, HONEY, SAUSSUREA LAPPA, AND NIGELLA SATIVA

Background:Covid-19 has become pandemic in the World, including Indonesia. Our last study showed that HSF could serve as an immunomodulator. Using the exact search, we found that the most immuno-dominant SARS-COV2 epitope, namely A spike protein epitope, B envelope protein epitope, and C membrane protein epitope, we concise to be HF Materials and Methods:We used to post only control design study and mice as an animal model. The research divided mice into four groups, and the first group as control received PBS as a placebo. The second, three, and last four groups gave HF, HSN, and HFHSN (combine HF and HSN). All of the regiment enters the mouth with a special sonde to reach the gastrointestinal organ. We gave HF every week three times and HSN once a day. After administration regiments for a long three weeks, we sacrificed the mice. We evaluated cellular immune responses that are Th-2, Th-17, and NK cells. We check for humoral immune response, TGF-β,IL-17A, IL-4, IgG,IL-4, β-defensin, and s-IgA. Results:Highest profile cellular immunity HF, HSN, and HFHSN were NK cell, Th-2 and Th-17, and the last NK cell, respectively. After that which in humoral immunity, the domination response IgG and IL-4 were HF. But HSN and HFHSN dominated for s-IgA and β-defensin production. By using the study Bio-Informatica, we found HF. Conclusion: If the results of this study are continued to the clinical trial level, it is necessary to recommend additional markers such as CTL (s-IgA and β-defensin in lung tissue)and CPE assay.

Comparison of purified psoralen-inactivated and formalin-inactivated dengue vaccines in mice and nonhuman primates

Dengue fever, caused by dengue viruses (DENV 1–4) is a leading cause of illness and death in the tropics and subtropics. Therefore, an effective vaccine is urgently needed. Currently, the only available licensed dengue vaccine is a chimeric live attenuated vaccine that shows varying efficacy depending on serotype, age and baseline DENV serostatus. Accordingly, a dengue vaccine that is effective in seronegative adults, children of all ages and in immunocompromised individuals is still needed. We are currently researching the use of psoralen to develop an inactivated tetravalent dengue vaccine. Unlike traditional formalin inactivation, psoralen inactivates pathogens at the nucleic acid level, potentially preserving envelope protein epitopes important for protective anti-dengue immune responses. We prepared highly purified monovalent vaccine lots of formalin- and psoralen-inactivated DENV 1–4, using Capto DeVirS and Capto Core 700 resin based column chromatography. Tetravalent psoralen-inactivated vaccines (PsIV) and formalin-inactivated vaccines (FIV) were prepared by combining the four monovalent vaccines. Mice were immunized with either a low or high dose of PsIV or FIV to evaluate the immunogenicity of monovalent as well as tetravalent formulations of each inactivation method. In general, the monovalent and tetravalent PsIVs elicited equivalent or higher titers of neutralizing antibodies to DENV than the FIV dengue vaccines and this response was dose dependent. The immunogenicity of tetravalent dengue PsIVs and FIVs were also evaluated in nonhuman primates (NHPs). Consistent with what was observed in mice, significantly higher neutralizing antibody titers for each dengue serotype were observed in the NHPs vaccinated with the tetravalent dengue PsIV compared to those vaccinated with the tetravalent dengue FIV, indicative of the importance of envelope protein epitope preservation during psoralen inactivation of DENV.

Broadly Neutralizing Antibodies for HIV Prevention.

In the last decade, over a dozen potent broadly neutralizing antibodies (bnAbs) to several HIV envelope protein epitopes have been identified, and their in vitro neutralization profiles have been defined. Many have demonstrated prevention efficacy in preclinical trials and favorable safety and pharmacokinetic profiles in early human clinical trials. The first human prevention efficacy trials using 10 sequential, every-two-month administrations of a single anti-HIV bnAb are anticipated to conclude in 2020. Combinations of complementary bnAbs and multi-specific bnAbs exhibit improved breadth and potency over most individual antibodies and are entering advanced clinical development. Genetic engineering of the Fc regions has markedly improved bnAb half-life, increased mucosal tissue concentrations of antibodies (especially in the genital tract), and enhanced immunomodulatory and Fc effector functionality, all of which improve antibodies' preventative and therapeutic potential. Human-derived monoclonal antibodies are likely to enter the realm of primary care prevention and therapy for viral infections in the near future.

Highly conserved epitopes of DENV structural and non-structural proteins: Candidates for universal vaccine targets

Dengue is a severe emerging arthropod borne viral disease occurring globally. Around two fifths of the world's population, or up to 3.9 billion people, are at a risk of dengue infection. Infection induces a life-long protective immunity to the homologous serotype but confers only partial and transient protection against subsequent infection caused by other serotypes. Thus, there is a need for a vaccine which is capable of providing a life- long protection against all the serotypes of dengue virus.In our study, comparative genomics of Dengue virus (DENV) was conducted to explore potential candidates for novel vaccine targets. From our analysis we successfully found 100% conserved epitopes in Envelope protein (RCPTQGE); NS3 (SAAQRRGR, PGTSGSPI); NS4A (QRTPQDNQL); NS4B (LQAKATREAQKRA) and NS5 proteins (QRGSGQV) in all DENV serotypes. Some serotype specific conserved motifs were also found in NS1, NS5, Capsid, PrM and Envelope proteins. Using comparative genomics and immunoinformatics approach, we could find conserved epitopes which can be explored as peptide vaccine candidates to combat dengue worldwide. Serotype specific epitopes can also be exploited for rapid diagnostics. All ten proteins are explored to find the conserved epitopes in DENV serotypes, thus making it the most extensively studied viral genome so far.

Development and characterization of a human monoclonal antibody targeting the N-terminal region of hepatitis C virus envelope glycoprotein E1

Monoclonal antibodies (mAbs) targeting the hepatitis C virus (HCV) envelope have been raised mainly against envelope protein 2 (E2), while the antigenic epitopes of envelope protein 1 (E1) are not fully identified. Here we describe the detailed characterization of a human mAb, designated A6, generated from an HCV genotype 1b infected patient. ELISA results showed reactivity of mAb A6 to full-length HCV E1E2 of genotypes 1a, 1b and 2a. Epitope mapping identified a region spanning amino acids 230–239 within the N-terminal region of E1 as critical for binding. Antibody binding to this epitope was not conformation dependent. Neutralization assays showed that mAb A6 lacks neutralizing capacity and does not interfere with the activity of known neutralizing antibodies. In summary, mAb A6 is an important tool to study the structure and function of E1 within the viral envelope, a crucial step in the development of an effective prophylactic HCV vaccine.

Activation of Toll-like receptor 9 and production of epitope specific antibody by liposome-encapsulated CpG-DNA

Several investigators have shown that CpG-DNA has outstanding effects as a Th1-responsive adjuvant and that its potent adjuvant effects are enhanced by encapsulation with a liposome of proper composition. In this study, we showed that encapsulation with phosphatidyl-Β-oleoyl-γ-palmitoyl ethanolamine (DOPE): cholesterol hemisuccinate (CHEMS) complex enhances the immunostimulatory activity of CpG DNA and the binding of CpG-DNA to TLR9. We also examined involvement of myeloid differentiation protein (MyD88) and NF-κB activation in liposome-encapsulated CpG-DNA-induced IL-8 promoter activation. In this manuscript, the natural phosphodiester bond CpG-DNA encapsulated by DOPE : CHEMS complex is designated as Lipoplex(O). Importantly, we successfully screened B cell epitopes of envelope protein (E protein) of hepatitis C virus (HCV-E) and attachment glycoprotein G of human respiratory syncytial virus (HRSV-G) by immunization with complexes of several peptides and Lipoplex(O) without carriers. Therefore, Lipoplex(O) is potentially applicable as a universal adjuvant for peptide-based epitope screening and antibody production.

Molecular and Biological Changes Associated with HeLa Cell Attenuation of Wild-Type Yellow Fever Virus

Six passages of the mosquito-borne flavivirus yellow fever (YF) wild-type strain Asibi in HeLa cells attenuated the virus for monkeys and newborn mice and resulted in loss of mosquito competence. Attenuation after the passage in HeLa cells was not unique to YF virus strain Asibi as demonstrated by the HeLa passage attenuation of wild-type YF virus strain French viscerotropic virus and YF vaccine virus 17D-204 for newborn mice. In contrast, wild-type strain Dakar 1279 and the French neurotropic vaccine virus remained virulent for newborn mice after six passages in HeLa cells. Thus not all strains of YF virus can be attenuated by passage in HeLa cells. Attenuation of YF virus strains Asibi and French viscerotropic virus was accompanied by alterations in the antigenic and biological properties of the viruses, including changes to envelope protein epitopes. Attenuation for newborn mice was coincidental with the acquisition by the HeLa-passaged viruses of the vaccine-specific envelope protein epitope recognized by monoclonal antibody H5. This suggests that this conformational change may play a role in the attenuation process. Wild-type Dakar 1279, which remained virulent for newborn mice after passage in HeLa cells, retained its wild-type antigenic character. The genome of Asibi HeLa p6 virus differed from wild-type Asibi virus by 29 nucleotides that encoded 10 amino acid substitutions: 5 in the envelope protein, 1 in NS2A, 3 in NS4B, and 1 in NS5. The substitution at NS4B-95 is seen in three different attenuation processes of wild-type YF virus, leading us to speculate that it is involved in the attenuation of virulence of wild-type strain Asibi.

Immunization with a mouse mammary tumour virus envelope protein epitope protects against tumour formation without inhibition of the virus infection.

BALB/c mice were immunized with the EP3 surface epitope of the mouse mammary tumour virus (MMTV) gp52 envelope protein before systemic infection with MMTV(C3H) or MMTV(SW). Analysis of the successive stages of the virus infection showed that although these mice were protected against mammary tumour formation, earlier stages of the infection were not inhibited, as reflected by the persisting superantigen-induced activation and deletion of Vbeta-specific T cells. Transplacental transfer of maternal anti-EP3 immunoglobulins to newborns did not protect them from infection through the Peyer's patches. Preincubation of the MMTVs with an anti-EP3 serum before injection, however, successfully inhibited the early stages of the infection. Results from this study show that to inhibit infection by MMTV efficiently, the virus must be neutralized before its interaction with the cell membrane, and that the affinity of the virus-membrane interaction is higher than that of the virus-antibody interaction.

A mouse-attenuated envelope protein variant of Murray Valley encephalitis virus with altered fusion activity.

A neutralization escape variant of Murray Valley encephalitis virus (MVE), of low neuroinvasiveness in mice and with low haemagglutination activity, had a reduced rate of replication in cultured cells during the early phase of infection compared to wild-type MVE. The variant was internalized by Vero cells at a similar rate to wild-type MVE at pH 7.4, but had reduced pH-dependent membrane fusion activity. In fusion-from-within experiments in infected mosquito (C6/36) cells, the variant had a lowered pH threshold for induction of fusion, which occurred at a reduced rate and to a lesser extent than for wild-type virus. Fusion was inhibited by monoclonal antibodies specific for envelope protein epitopes E-5 and E-8, which were implicated as determinants of fusion. These observations are discussed in relation to the regulation of MVE replication by fusion of the viral envelope with endosome membranes and, in turn, how rates of replication may affect neuroinvasion.

Epitope analysis of tick-borne encephalitis (TBE) complex viruses using monoclonal antibodies to envelope glycoprotein of TBE virus (persulcatus subtype)

The arrangement of envelope protein epitopes of tick-borne encephalitis viruses (TBEV) (persulcatus or eastern subtype, Sofjin strain and ricinus or western subtype, Minsk-256 strain) and Kyasanur Forest disease virus (KFDV) was investigated using competitive binding of monoclonal antibodies against the Sofjin E protein. The E protein of TBEV Sofjin strain forms three antigenic domains: E1, E2 and E3, represented by 12, 9 and 2 epitopes respectively; two additional epitopes stand alone. Domains E1 and E2 are heterogeneous. On the epitope map of the Minsk-256 strain domain E3 remains intact, domains E1 and E2 overlap and the relative arrangement of virus-neutralizing epitopes from E1 and E2 domains is changed. The epitope map of KFDV is significantly dissimilar to TBEV. The viruses can be distinguished by epitopes with identical serological reactivity. A satisfactory agreement between our epitope maps and previously published antigenic models of flavivirus envelope protein (Guirakhoo et al., 1989; Mandl et al., 1989a) was observed. The main difference of our map is that domains corresponding to domains B and C (Sofjin strain) and A, B and C (Minsk-256 strain) in Heinz's model are overlapping. The results of competition analysis depend on the nature of the antigen (virion or purified protein) and the immunoassay technique.

CD4-Independent inhibition of lymphocyte proliferation mediated by HIV-1 envelope glycoproteins

The cytopathic effects of HIV-1 produced by direct infection of human T cells do not account for the disproportionate loss of CD4-positive lymphocytes during the course of HIV infection. Previous studies have demonstrated the inhibition of uninfected human T cell activation and proliferation by the HIV-1 envelope glycoproteins, presumably due to gp120-CD4 interactions. To examine the ability of HIV-1 to inhibit T cell proliferation in the absence of both direct infection and gp120-CD4 interactions, we tested the effect of HIV-1 on mouse T cell proliferation. Culture media containing HIV-1 released from infected cells inhibited T lymphocyte proliferation in response to interleukin-2 (IL-2). Studies to explore the mechanism of this inhibition suggested that the decrease in proliferation resulted from interactions between HIV-1 and the mouse cells, but did not involve IL-2/IL-2 receptor interactions. We used monoclonal antibodies to demonstrate that the HIV-1 envelope glycoproteins were required for the inhibition of murine T cell proliferation. Anti-gpl 20 antibodies completely restored proliferation, indicating that the surface protein gp120 was primarily required for the inhibition of proliferation. However, antibodies directed against the transmembrane protein of HIV-1 (gp41) also partially restored lymphocyte proliferation. The functional significance of the HIV-1 envelope protein epitopes recognized by the monoclonal antibodies is discussed.

Identification of envelope protein epitopes that are important in the attenuation process of wild-type yellow fever virus

Monoclonal antibodies (MAbs) have been prepared against vaccine and wild-type strains of yellow fever (YF) virus, and envelope protein epitopes specific for vaccine (MAbs H5 and H6) and wild-type (MAbs S17, S18, S24, and S56) strains of YF virus have been identified. Wild-type YF virus FVV, Dakar 1279, and B4.1 were each given six passages in HeLa cells. FVV and B4.1 were attenuated for newborn mice following passage in HeLa cells, whereas Dakar 1279 was not. Examination of the envelope proteins of the viruses with 87 MAbs showed that attenuated viruses gained only the vaccine epitope recognized by MAb H5 and lost wild-type epitopes recognized by MAbs S17, S18, and S24 whereas the nonattenuated Dakar 1279 HeLa p6 virus did not gain the vaccine epitope, retained the wild-type epitopes, and showed no other physical epitope alterations. MAb neutralization-resistant (MAbr) escape variants generated by using wild-type-specific MAbs S18 and S24 were found to lose the epitopes recognized by MAbs S18 and S24 and to acquire the epitope recognized by vaccine-specific MAb H5. In addition, the MAbr variants became attenuated for mice. Thus, the data presented in this paper indicate that acquisition of vaccine epitopes and loss of wild-type epitopes on the envelope protein are directly involved in the attenuation process of YF virus and suggest that the envelope protein is one of the genes encoding determinants of YF virus pathogenicity.

Variation in the biological function of envelope protein epitopes of yellow fever vaccine viruses detected with monoclonal antibodies

Three different virus strains (17D-204, 17DD and the French neurotropic vaccine) have been used as live attenuated yellow fever (YF) vaccines and are manufactured in different centres around the world. The envelope proteins of these vaccine viruses were examined and compared using mouse monoclonal antibodies (MAbs) in haemagglutination inhibition (HAI) and neutralization (N) tests. The epitopes eliciting HAI and/or N were found to vary depending on the virus examined. Such variation was also found between vaccine viruses of the same strain manufactured in different centres. These data were confirmed by the use of mouse polyclonal antisera. On the basis of the MAb results in HAI tests a dendrogram of the similarity coefficients between the viruses was constructed and showed that the viruses could be placed into three major groups. Thus, it is concluded that YF vaccines manufactured in different centres are antigenically distinct as recognized by the mouse immune system.

Attenuation of wild-type yellow fever virus by passage in HeLa cells

During the 1960s three different research groups reported that passage of wild-type yellow fever (YF) virus [strain Asibi (YF-Asibi)] in HeLa cells resulted in attenuation of the virus for monkeys so that the virus no longer caused viscerotropic disease. We have repeated and extended this observation to analyse the process of attenuation of YF virus during cell culture passage. A large plaque (LP) variant of YF-Asibi virus became attenuated for both monkeys and mice following six serial subcultures in HeLa cells (YF-Asibi-LP HeLa p6). Thus, attenuation was probably due to a genetic change in the virus population rather than to selective enrichment of a pre-existing variant of YF-Asibi-LP virus. No evidence was obtained to implicate defective interfering particles in the attenuation process. Comparison of the YF-Asibi-LP viruses before and after passage in HeLa cells, using a panel of envelope protein-reactive monoclonal antibodies (MAbs), showed that MAbs which specifically neutralize YF-Asibi-LP virus, and not YF 17D-204 vaccine virus, also neutralized YF-Asibi-LP HeLa p6. This indicated that the epitopes involved in the biological process of neutralization were not altered during attenuation. However, two MAbs that recognize envelope protein epitopes did distinguish between HeLa- and non-HeLa-passaged YF-Asibi-LP virus. One of these (MAb 117) which is YF wild-type-specific, recognized YF-Asibi-LP virus but not YF-Asibi-LP HeLa p6 virus, whereas the other (MAb411), which is YF vaccine-specific, recognized YF-Asibi-LP HeLa p6 virus but not YF-Asibi-LP virus. These results suggest that antigenic changes in the viral envelope protein may determine the relative virulence or attenuation of YF virus.

In vitro inhibition of hemopoietic cell line growth by hepatitis B virus

The effects of hepatitis B virus (HBV) on established human cell lines of various tissue origins were evaluated by clonal or colorimetric assays in methylcellulose culture. HBV exposure inhibited the growth of six hemopoietic cell lines, while similar incubation did not affect the growth of seven nonhemopoietic carcinoma cell lines of breast, colon, liver, and stomach origin. The inhibition of hemopoietic cell line colony formation was dependent on the presence of intact viral (Dane) particles and the ratio of exposure of virions to cells and was reversible with antibodies to pre-S1, pre-S2, and S envelope protein epitopes. Purified HBV DNA, surface antigen pre-S antigens, and core antigen did not inhibit cell line growth. These results further demonstrate the tropism of HBV for cells of hemopoietic origin, confirming our previous findings on the effects of HBV on the growth of normal bone marrow progenitor cells in vitro. Established human tissue culture cell lines may be used to study the interactions of hemopoietic cells with HBV.