RESUMEN

The Red Queen Hypothesis (RQH), derived from Lewis Carroll's "Through the Looking-Glass", postulates that organisms must continually adapt in response to each other to maintain relative fitness. Within the context of host-pathogen interactions, the RQH implies an evolutionary arms race, wherein viruses evolve to exploit hosts and hosts evolve to resist viral invasion. This study delves into the dynamics of the RQH in the context of virus-cell interactions, specifically focusing on virus receptors and cell receptors. We observed multiple virus-host systems and noted patterns of co-evolution. As viruses evolved receptor-binding proteins to effectively engage with cell receptors, cells countered by altering their receptor genes. This ongoing mutual adaptation cycle has influenced the molecular intricacies of receptor-ligand interactions. Our data supports the RQH as a driving force behind the diversification and specialization of both viral and host cell receptors. Understanding this co-evolutionary dance offers insights into the unpredictability of emerging viral diseases and potential therapeutic interventions. Future research is crucial to dissect the nuanced molecular changes and the broader ecological consequences of this ever-evolving battle. Here, we combine phylogenetic inferences, structural modeling, and molecular dynamics analyses to describe the epidemiological characteristics of major Brazilian DENV strains that circulated from 1990 to 2022 from a combined perspective, thus providing us with a more detailed picture on the dynamics of such interactions over time.

Asunto(s)

Moléculas de Adhesión Celular , Virus del Dengue , Evolución Molecular , Interacciones Huésped-Patógeno , Receptores de Superficie Celular , Proteínas del Envoltorio Viral , Envoltura Viral , Humanos , Brasil , Moléculas de Adhesión Celular/metabolismo , Moléculas de Adhesión Celular/genética , Moléculas de Adhesión Celular/química , Dengue/virología , Virus del Dengue/genética , Virus del Dengue/metabolismo , Interacciones Huésped-Patógeno/genética , Lectinas Tipo C/metabolismo , Lectinas Tipo C/genética , Lectinas Tipo C/química , Simulación de Dinámica Molecular , Filogenia , Unión Proteica , Receptores de Superficie Celular/metabolismo , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/química , Receptores Virales/metabolismo , Receptores Virales/química , Receptores Virales/genética , Envoltura Viral/metabolismo , Proteínas del Envoltorio Viral/genética , Proteínas del Envoltorio Viral/metabolismo , Proteínas del Envoltorio Viral/química

RESUMEN

The Dengue virus complex (DENV), formed by four serotypes, constitutes the most important arbovirus affecting humans. The structural domain III of their envelope protein (DIII) elicits strongly neutralizing serotype-specific antibodies. Contrasting results have been obtained regarding their role in the serum neutralizing activity of infected patients. We used a DENV immune serum from a secondary infection to examine the impact of characterizing the anti-DIII antibody response after affinity purification with recombinant DIII proteins to eliminate potential interferences from the interactions with human plasma proteins and other anti-DENV antibodies. Total anti-DENV IgG repertoire and anti-DIIIE antibodies were compared in functionality. In early convalescence, reactivity of anti-DIII antibodies is serotype specific and exhibits the strongest reactivity with infecting serotypes. Purification of anti-DIII antibodies emphasizes the reactivity profile as compared to total IgG fraction and serum. Serotype-specificity of the virus neutralization activity correlated with the apparent kD of the binding to recombinant DIIIs.

Asunto(s)

Virus del Dengue , Dengue , Humanos , Virus del Dengue/genética , Anticuerpos Antivirales , Convalecencia , Anticuerpos Neutralizantes , Inmunoglobulina G/metabolismo , Proteínas del Envoltorio Viral/química

RESUMEN

Introduction: In the present study we evaluated the features of different recombinant forms of Zika virus (ZIKV) proteins produced in either bacterial (Eschericha coli) or insect cells (Drosophila melanogaster). The ZIKV-envelope glycoprotein (EZIKV) is responsible for virus entry into host cells, is the main target of neutralizing antibodies and has been used as a target antigen either for serological tests or for the development of subunit vaccines. The EZIKV is composed of three structural and functional domains (EDI, EDII, and EDIII), which share extensive sequence conservation with the corresponding counterparts expressed by other flaviviruses, particularly the different dengue virus (DENV) subtypes. Methods: In this study, we carried out a systematic comparison of the antigenicity and immunogenicity of recombinant EZIKV, EDI/IIZIKV and EDIIIZIKV produced in E. coli BL21 and Drosophila S2 cells. For the antigenicity analysis we collected 88 serum samples from ZIKV-infected participants and 57 serum samples from DENV-infected. For immunogenicity, C57BL/6 mice were immunized with two doses of EZIKV, EDI/IIZIKV and EDIIIZIKV produced in E. coli BL21 and Drosophila S2 cells to evaluate humoral and cellular immune response. In addition, AG129 mice were immunized with EZIKV and then challenge with ZIKV. Results: Testing of samples collected from ZIKV-infected and DENV-infected participants demonstrated that the EZIKV and EDIIIZIKV produced in BL21 cells presented better sensitivity and specificity compared to proteins produced in S2 cells. In vivo analyses were carried out with C57BL/6 mice and the results indicated that, despite similar immunogenicity, antigens produced in S2 cells, particularly EZIKV and EDIIIZIKV, induced higher ZIKV-neutralizing antibody levels in vaccinated mice. In addition, immunization with EZIKV expressed in S2 cells delayed the onset of symptoms and increased survival rates in immunocompromised mice. All recombinant antigens, either produced in bacteria or insect cells, induced antigen-specific CD4+ and CD8+ T cell responses. Conclusion: In conclusion, the present study highlights the differences in antigenicity and immunogenicity of recombinant ZIKV antigens produced in two heterologous protein expression systems.

Asunto(s)

Infección por el Virus Zika , Virus Zika , Animales , Ratones , Virus Zika/genética , Proteínas del Envoltorio Viral/química , Anticuerpos Antivirales , Drosophila melanogaster , Escherichia coli/genética , Ratones Endogámicos C57BL , Vacunas de Subunidad

RESUMEN

Vaccine development against dengue virus is challenging because of the antibody-dependent enhancement of infection (ADE), which causes severe disease. Consecutive infections by Zika (ZIKV) and/or dengue viruses (DENV), or vaccination can predispose to ADE. Current vaccines and vaccine candidates contain the complete envelope viral protein, with epitopes that can raise antibodies causing ADE. We used the envelope dimer epitope (EDE), which induces neutralizing antibodies that do not elicit ADE, to design a vaccine against both flaviviruses. However, EDE is a discontinuous quaternary epitope that cannot be isolated from the E protein without other epitopes. Utilizing phage display, we selected three peptides that mimic the EDE. Free mimotopes were disordered and did not elicit an immune response. After their display on adeno-associated virus (AAV) capsids (VLP), they recovered their structure and were recognized by an EDE-specific antibody. Characterization by cryo-EM and enzyme-linked immunosorbent assay confirmed the correct display of a mimotope on the surface of the AAV VLP and its recognition by the specific antibody. Immunization with the AAV VLP displaying one of the mimotopes induced antibodies that recognized ZIKV and DENV. This work provides the basis for developing a Zika and dengue virus vaccine candidate that will not induce ADE.

Asunto(s)

Virus del Dengue , Dengue , Vacunas , Infección por el Virus Zika , Virus Zika , Humanos , Infección por el Virus Zika/prevención & control , Virus del Dengue/química , Dengue/prevención & control , Anticuerpos Antivirales , Proteínas del Envoltorio Viral/química , Anticuerpos Neutralizantes , Epítopos , Reacciones Cruzadas

RESUMEN

The binding of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein to the angiotensin-converting enzyme 2 (ACE2) receptor expressed on the host cells is a critical initial step for viral infection. This interaction is blocked through competitive inhibition by soluble ACE2 protein. Therefore, developing high-affinity and cost-effective ACE2 mimetic ligands that disrupt this protein-protein interaction is a promising strategy for viral diagnostics and therapy. We employed human and plant defensins, a class of small (2-5 kDa) and highly stable proteins containing solvent-exposed alpha-helix, conformationally constrained by two disulfide bonds. Therefore, we engineered the amino acid residues on the constrained alpha-helix of defensins to mimic the critical residues on the ACE2 helix 1 that interact with the SARS-CoV-2 spike protein. The engineered proteins (h-deface2, p-deface2, and p-deface2-MUT) were soluble and purified to homogeneity with a high yield from a bacterial expression system. The proteins demonstrated exceptional thermostability (Tm 70.7°C), high-affinity binding to the spike protein with apparent Kd values of 54.4 ± 11.3, 33.5 ± 8.2, and 14.4 ± 3.5 nM for h-deface2, p-deface2, and p-deface2-MUT, respectively, and were used in a diagnostic assay that detected SARS-CoV-2 neutralizing antibodies. This work addresses the challenge of developing helical ACE2 mimetics by demonstrating that defensins provide promising scaffolds to engineer alpha-helices in a constrained form for designing of high-affinity ligands.

Asunto(s)

COVID-19 , Glicoproteína de la Espiga del Coronavirus , Enzima Convertidora de Angiotensina 2/genética , Defensinas , Humanos , Ligandos , Glicoproteínas de Membrana/química , Peptidil-Dipeptidasa A/metabolismo , Conformación Proteica en Hélice alfa , SARS-CoV-2/genética , Glicoproteína de la Espiga del Coronavirus/genética , Proteínas del Envoltorio Viral/química

RESUMEN

Zika virus (ZIKV) is an arbovirus from the Flaviviridae family and Flavivirus genus. Neurological events have been associated with ZIKV-infected individuals, such as Guillain-Barré syndrome, an autoimmune acute neuropathy that causes nerve demyelination and can induce paralysis. With the increase of ZIKV infection incidence in 2015, malformation and microcephaly cases in newborns have grown considerably, which suggested congenital transmission. Therefore, the development of an effective vaccine against ZIKV became an urgent need. Live attenuated vaccines present some theoretical risks for administration in pregnant women. Thus, we developed an in silico multiepitope vaccine against ZIKV. All structural and non-structural proteins were investigated using immunoinformatics tools designed for the prediction of CD4 + and CD8 + T cell epitopes. We selected 13 CD8 + and 12 CD4 + T cell epitopes considering parameters such as binding affinity to HLA class I and II molecules, promiscuity based on the number of different HLA alleles that bind to the epitopes, and immunogenicity. ZIKV Envelope protein domain III (EDIII) was added to the vaccine construct, creating a hybrid protein domain-multiepitope vaccine. Three high scoring continuous and two discontinuous B cell epitopes were found in EDIII. Aiming to increase the candidate vaccine antigenicity even further, we tested secondary and tertiary structures and physicochemical parameters of the vaccine conjugated to four different protein adjuvants: flagellin, 50S ribosomal protein L7/L12, heparin-binding hemagglutinin, or RS09 synthetic peptide. The addition of the flagellin adjuvant increased the vaccine's predicted antigenicity. In silico predictions revealed that the protein is a probable antigen, non-allergenic and predicted to be stable. The vaccine's average population coverage is estimated to be 87.86%, which indicates it can be administered worldwide. Peripheral Blood Mononuclear Cells (PBMC) of individuals with previous ZIKV infection were tested for cytokine production in response to the pool of CD4 and CD8 ZIKV peptide selected. CD4 + and CD8 + T cells showed significant production of IFN-γ upon stimulation and IL-2 production was also detected by CD8 + T cells, which indicated the potential of our peptides to be recognized by specific T cells and induce immune response. In conclusion, we developed an in silico universal vaccine predicted to induce broad and high-coverage cellular and humoral immune responses against ZIKV, which can be a good candidate for posterior in vivo validation.

Asunto(s)

Biología Computacional/métodos , Epítopos de Linfocito B/inmunología , Epítopos de Linfocito T/inmunología , Proteínas Virales/inmunología , Vacunas Virales/química , Vacunas Virales/inmunología , Virus Zika/inmunología , Adyuvantes Inmunológicos , Autoinmunidad , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Citocinas/metabolismo , Epítopos de Linfocito B/química , Epítopos de Linfocito T/química , Flagelina/inmunología , Humanos , Inmunidad Humoral , Inmunogenicidad Vacunal , Lectinas/inmunología , Leucocitos Mononucleares/inmunología , Péptidos/inmunología , Filogenia , Proteínas Ribosómicas/inmunología , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/inmunología , Proteínas Virales/química , Virus Zika/química , Infección por el Virus Zika/inmunología , Infección por el Virus Zika/virología

RESUMEN

Baculoviruses are insect pathogens that are characterized by assembling the viral dsDNA into two different enveloped virions during an infective cycle: occluded virions (ODVs; immersed in a protein matrix known as occlusion body) and budded virions (BVs). ODVs are responsible for the primary infection in midgut cells of susceptible larvae thanks to the per os infectivity factor (PIF) complex, composed of at least nine essential viral proteins. Among them, P74 is a crucial factor whose activity has been identified as virus-specific. In this work, the p74 gene from AcMNPV was pseudogenized using CRISPR/Cas9 technology and then complemented with wild-type alleles from SeMNPV and HearSNPV species, as well as chimeras combining the P74 amino and carboxyl domains. The results on Spodoptera exigua and Rachiplusia nu larvae showed that an amino terminal sector of P74 (lacking two potential transmembrane regions but possessing a putative nuclear export signal) is sufficient to restore the virus infectivity whether alone or fused to the P74 transmembrane regions of the other evaluated viral species. These results provide novel information about the functional role of P74 and delimit the region on which mutagenesis could be applied to enhance viral activity and, thus, produce better biopesticides.

Asunto(s)

Nucleopoliedrovirus/química , Nucleopoliedrovirus/fisiología , Spodoptera/virología , Proteínas del Envoltorio Viral/química , Secuencias de Aminoácidos , Animales , Sistemas CRISPR-Cas , Prueba de Complementación Genética , Larva/virología , Mariposas Nocturnas/virología , Nucleopoliedrovirus/genética , Filogenia , Dominios Proteicos , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/metabolismo , Células Sf9 , Proteínas del Envoltorio Viral/genética , Proteínas del Envoltorio Viral/metabolismo

RESUMEN

Dengue virus (DENV) is the most prevalent pathogen of the Flaviviridae family. Due to the considerable increase in DENV incidence and spread, symptoms such as CNS involvement have increased. Heparan sulphate (HS) was the first molecule identified as an adhesion factor for DENV in mammalian cells. Viral phenotypes with different HS interactions are associated with various clinical symptoms, including neurological alterations. Here, using in silico analyses, in vitro studies, and the in vivo mouse model, we characterized two natural circulating DENV3 genotype I (GI) lineage 1 (L1) in Brazil-DENV3 MG-20 (from Minas Gerais) and DENV3 PV_BR (from Rondônia) that present divergent neurovirulent profiles and sensitivity to sulphated molecules. We identified substitutions at the viral envelope (E) in positions 62 and 123 as likely responsible for the differences in neurovirulence. The E62K and E123Q substitutions in DENV3 MG-20 and DENV3 PV_BR, respectively, greatly influenced in silico electrostatic density and heparin docking results. In vivo, mice inoculated with DENV3 MG-20 died, but not those infected with DENV3 PV_BR. The clinical symptoms, such as paralysis of the lower limbs and meningoencephalitis, and histopathology, also differed between the inoculated groups. In vitro heparin and heparinases assays further demonstrated the biological impact of these substitutions. Other characteristics that have been previously associated with alterations in cell tropism and neurovirulence, such as changes in the size of lysis plaques and differences in cytopathic effects in glioblastoma cells, were also observed.

Asunto(s)

Virus del Dengue/clasificación , Virus del Dengue/genética , Dengue/virología , Genotipo , Heparitina Sulfato/metabolismo , Proteínas del Envoltorio Viral/química , Animales , Sitios de Unión , Encéfalo/patología , Comunicación Celular , Línea Celular , Dengue/patología , Virus del Dengue/fisiología , Modelos Animales de Enfermedad , Femenino , Heparina , Interacciones Huésped-Patógeno/fisiología , Humanos , Ratones , Ratones Endogámicos BALB C , Simulación del Acoplamiento Molecular , Fenotipo , Filogenia , Conformación Proteica , Proteínas del Envoltorio Viral/clasificación , Proteínas del Envoltorio Viral/genética , Virulencia , Acoplamiento Viral

RESUMEN

Pestivirus envelope protein E2 is crucial to virus infection and accomplishes virus-receptor interaction during entry. However, mapping of E2 residues mediating these interactions has remained unexplored. In this study, to investigate the structure-function relationship for a ß-hairpin motif exposed to the solvent in the crystal structure of bovine viral diarrhea virus (BVDV) E2, we designed two amino acidic substitutions that result in a change of electrostatic potential. First, using wild type and mutant E2 expressed as soluble recombinant proteins, we found that the mutant protein had reduced binding to susceptible cells compared to wild type and diminished ability to inhibit BVDV infection, suggesting a lower affinity for BVDV receptors. We then analyzed the effect of ß-hairpin mutations in the context of recombinant viral particles. Mutant viruses recovered from cell culture supernatant after transfection of recombinant RNA had almost completely inhibited ability to re-infect susceptible cells, indicating an impact of mutations on BVDV infectivity. Finally, sequential passaging of the mutant virus resulted in the selection of a viral population in which ß-hairpin mutations reverted to the wild type sequence to restore infectivity. Taken together, our results show that this conserved region of the E2 protein is critical for the interaction with host cell receptors.

Asunto(s)

Virus de la Diarrea Viral Bovina/genética , Virus de la Diarrea Viral Bovina/metabolismo , Receptores Virales/metabolismo , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/metabolismo , Internalización del Virus , Sustitución de Aminoácidos , Animales , Bovinos , Línea Celular , Virus de la Diarrea Viral Bovina/química , Secuencias Invertidas Repetidas/fisiología , Unión Proteica , Proteínas del Envoltorio Viral/genética

RESUMEN

The flavivirus are emerging and re-emerging arthropod-borne pathogens responsible for significant mortality and morbidity worldwide. The genus comprises more than 70 viruses, and despite genomic and structural similarities, infections by different flaviviruses result in different clinical presentations. In the absence of a safe and effective vaccine against these infections, the search for new strategies to inhibit viral infection is necessary. The life cycle of arboviruses begins with the entry process composed of multiple steps: attachment, internalization, endosomal escape and capsid uncoating. This mini-review describes factors and mechanisms involved in the viral entry as events required to take over the cellular machinery and host factors and cellular pathways commonly used by flaviviruses as possible approaches for developing broad-spectrum antiviral drugs.

Asunto(s)

Infecciones por Flavivirus/virología , Flavivirus/fisiología , Internalización del Virus , Animales , Antivirales/metabolismo , Antivirales/farmacología , Endocitosis , Flavivirus/efectos de los fármacos , Flavivirus/patogenicidad , Infecciones por Flavivirus/tratamiento farmacológico , Interacciones Huésped-Patógeno , Humanos , Receptores Virales/metabolismo , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/metabolismo , Internalización del Virus/efectos de los fármacos , Replicación Viral

RESUMEN

Nanoadjuvants that combine immunostimulatory properties and delivery systems reportedly bestow major improvements on the efficacy of recombinant, protein-based vaccines. Among these, self-assembled micellar formulations named ISCOMs (immune stimulating complexes) show a great ability to trigger powerful immunological responses against infectious pathogens. Here, a nanoadjuvant preparation, based on saponins from Quillaja brasiliensis, was evaluated together with an experimental Zika virus (ZIKV) vaccine (IQB80-zEDIII) and compared to an equivalent vaccine with alum as the standard adjuvant. The preparations were administered to mice in two doses (on days zero and 14) and immune responses were evaluated on day 28 post-priming. Serum levels of anti-Zika virus IgG, IgG1, IgG2b, IgG2c, IgG3 were significantly increased by the nanoadjuvant vaccine, compared to the mice that received the alum-adjuvanted vaccine or the unadjuvanted vaccine. In addition, a robust production of neutralizing antibodies and in vitro splenocyte proliferative responses were observed in mice immunized with IQB80-zEDIII nanoformulated vaccine. Therefore, the IQB80-zEDIII recombinant preparation seems to be a suitable candidate vaccine for ZIKV. Overall, this study identified saponin-based delivery systems as an adequate adjuvant for recombinant ZIKV vaccines and has important implications for recombinant protein-based vaccine formulations against other flaviviruses and possibly enveloped viruses.

Asunto(s)

Adyuvantes Inmunológicos , ISCOMs/inmunología , Quillaja/química , Saponinas/inmunología , Proteínas del Envoltorio Viral/inmunología , Vacunas Virales/inmunología , Virus Zika/inmunología , Adyuvantes Inmunológicos/administración & dosificación , Animales , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , ISCOMs/administración & dosificación , Inmunogenicidad Vacunal , Linfocitos/inmunología , Ratones , Dominios Proteicos , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Saponinas/química , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/genética , Vacunas Virales/administración & dosificación

RESUMEN

Chikungunya virus (CHIKV) is a mosquito-borne pathogen that causes a disease characterized by the acute onset of fever accompanied by arthralgia and intense joint pain. Clinical similarities and cocirculation of this and other arboviruses in many tropical countries highlight the necessity for efficient and accessible diagnostic tools. CHIKV envelope proteins are highly conserved among alphaviruses and, particularly, the envelope 2 glycoprotein (CHIKV-E2) appears to be immunodominant and has a considerable serodiagnosis potential. Here, we investigate how glycosylation of CHIKV-E2 affects antigen/antibody interaction and how this affects the performance of CHIKV-E2-based Indirect ELISA tests. We compare two CHIKV-E2 recombinant antigens produced in different expression systems: prokaryotic-versus eukaryotic-made recombinant proteins. CHIKV-E2 antigens are expressed either in E. coli BL21(DE3)-a prokaryotic system unable to produce post-translational modifications-or in HEK-293T mammalian cells-a eukaryotic system able to add post-translational modifications, including glycosylation sites. Both prokaryotic and eukaryotic recombinant CHIKV-E2 react strongly to anti-CHIKV IgG antibodies, showing accuracy levels that are higher than 90%. However, the glycan-added viral antigen presents better sensitivity and specificity (85 and 98%) than the non-glycosylated antigen (81 and 71%, respectively) in anti-CHIKV IgM ELISA assays.

Asunto(s)

Anticuerpos Antivirales/sangre , Antígenos Virales/inmunología , Fiebre Chikungunya/diagnóstico , Virus Chikungunya/inmunología , Ensayo de Inmunoadsorción Enzimática , Pruebas Serológicas , Proteínas del Envoltorio Viral/inmunología , Antígenos Virales/biosíntesis , Antígenos Virales/química , Antígenos Virales/aislamiento & purificación , Escherichia coli , Glicosilación , Células HEK293 , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Polisacáridos , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/química , Proteínas Recombinantes/inmunología , Proteínas Recombinantes/aislamiento & purificación , Sensibilidad y Especificidad , Proteínas del Envoltorio Viral/biosíntesis , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/aislamiento & purificación

RESUMEN

The envelope (E) protein is an important target for antibodies in flavivirus. Literature reports that the mutation T198F, located at the domain I-II hinge of the E protein, regulates viral breathing and increases the accessibility of a distal cryptic epitope located on the fusion loop, having a direct impact in the neutralization of West Nile virus (WNV). Our study aimed to describe, using accelerated molecular dynamics simulations, the effects of the T198F mutation in the flexibility of the E protein of WNV and to elucidate the mechanism that regulates epitope accessibility. The simulation results revealed that the mutation favors the formation of alternative hydrogen bonds, hampering the bending movement between domains I and II. We hypothesized that this is the mechanism by which the T198F mutation, located at the middle of the protein, locks the distal cryptc epitope near a single preferred conformation, rendering it more prone to recognition by antibodies.

Asunto(s)

Simulación de Dinámica Molecular , Proteínas del Envoltorio Viral/metabolismo , Virus del Nilo Occidental/metabolismo , Anticuerpos Antivirales/inmunología , Epítopos/química , Epítopos/inmunología , Enlace de Hidrógeno , Mutación/genética , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/genética , Virus del Nilo Occidental/genética

RESUMEN

The SARS-CoV-2 virus has spread around the world. At this time, there is no vaccine that can help people prevent the spread of coronavirus. We are proposing amantadine as a drug that can be used to mitigate the effects of the virus. It is demonstrated by docking models how amantadine can exert its action on Coronavirus viroporin E.

Asunto(s)

Amantadina/uso terapéutico , Infecciones por Coronavirus/tratamiento farmacológico , Neumonía Viral/tratamiento farmacológico , Proteínas del Envoltorio Viral/química , Betacoronavirus , COVID-19 , Proteínas de la Envoltura de Coronavirus , Humanos , Canales Iónicos/química , Canales Iónicos/efectos de los fármacos , Ligandos , Simulación del Acoplamiento Molecular , Pandemias , Conformación Proteica , SARS-CoV-2 , Proteínas no Estructurales Virales/química , Proteínas no Estructurales Virales/efectos de los fármacos , Proteínas Viroporinas , Tratamiento Farmacológico de COVID-19

RESUMEN

On July 19, 2019, the World Health Organization declared the current Ebolavirus (EBOV) outbreak in Congo Democratic Republic (COD) a public health emergency of international concern. To address the potential threat of EBOV evolution outpacing antibody treatment and vaccine efforts, a detailed evolutionary analysis of EBOV strains circulating in different African countries was performed. Genome composition of EBOV strains was studied using multivariate statistical analysis. To investigate the patterns of evolution of EBOV strains, a Bayesian Markov Chain Monte Carlo approach was used. Two different genetic lineages, with a distinct genome composition gave rise to the recent EBOV outbreaks in central and western Africa. Strains isolated in COD in 2018 fall into two different genetic clusters, according to their geographical location of isolation. Different amino acid substitutions among strains from these two clusters have been found, particularly in NP, GP, and L proteins. Significant differences in codon and amino acid usage among clusters were found. Strains isolated in COD in 2018 belong to two distinct genetic clusters, with distinct codon and amino acid usage. Geographical diversity plays an important role in shaping the molecular evolution of EBOV populations.

Asunto(s)

Ebolavirus/genética , Evolución Molecular , Genoma Viral , Fiebre Hemorrágica Ebola/virología , África Central/epidemiología , África Occidental/epidemiología , Sustitución de Aminoácidos , Teorema de Bayes , Uso de Codones , Brotes de Enfermedades , Ebolavirus/aislamiento & purificación , Fiebre Hemorrágica Ebola/epidemiología , Humanos , Cadenas de Markov , Método de Montecarlo , Proteínas de la Nucleocápside/química , Proteínas de la Nucleocápside/genética , ARN Polimerasa Dependiente del ARN/química , ARN Polimerasa Dependiente del ARN/genética , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/genética

RESUMEN

Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that causes Chikungunya fever. CHIKV entered Mexico through the state of Chiapas in October 2014. To fully understand the Chikungunya fever outbreak that occurred in southern Chiapas during 2015, we evaluated 22 PCR-confirmed CHIKV-positive patients, identified CHIKV genetic variability, reconstructed viral dispersal, and assessed possible viral mutations. Viruses were isolated and E2, 6K, and E1 genes were sequenced. We applied phylogenetic and phylogeographic approaches, modeled mutations, and estimated selective pressure. Different CHIKV strains circulated in Chiapas during summer 2015. Three isolates grouped themselves in a well-supported clade. Estimates show that the outbreak started in Ciudad Hidalgo and posteriorly dispersed towards Tapachula and neighboring municipalities. We found six non-synonymous mutations in our isolates. Two mutations occurred in one isolate and the remaining mutations occurred in single isolates. Mutations E2 T116I and E2 K221R changed the protein surface in contact with the host cell receptors. We could not find positive selected sites in our CHIKV sequences from southern Chiapas. This is the first viral phylogeographic reconstruction in Mexico characterizing the CHIKV outbreak in southern Chiapas.

Asunto(s)

Fiebre Chikungunya/epidemiología , Fiebre Chikungunya/virología , Virus Chikungunya/genética , Fiebre Chikungunya/transmisión , Virus Chikungunya/clasificación , Virus Chikungunya/aislamiento & purificación , Brotes de Enfermedades , Variación Genética , Humanos , México/epidemiología , Modelos Moleculares , Filogenia , Filogeografía , ARN Viral/sangre , ARN Viral/genética , Selección Genética , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/genética

RESUMEN

The hantavirus envelope glycoproteins Gn and Gc mediate virion assembly and cell entry, with Gc driving fusion of viral and endosomal membranes. Although the X-ray structures and overall arrangement of Gn and Gc on the hantavirus spikes are known, their detailed interactions are not. Here we show that the lateral contacts between spikes are mediated by the same 2-fold contacts observed in Gc crystals at neutral pH, allowing the engineering of disulfide bonds to cross-link spikes. Disrupting the observed dimer interface affects particle assembly and overall spike stability. We further show that the spikes display a temperature-dependent dynamic behavior at neutral pH, alternating between 'open' and 'closed' forms. We show that the open form exposes the Gc fusion loops but is off-pathway for productive Gc-induced membrane fusion and cell entry. These data also provide crucial new insights for the design of optimized Gn/Gc immunogens to elicit protective immune responses.

Asunto(s)

Glicoproteínas/metabolismo , Orthohantavirus/metabolismo , Proteínas del Envoltorio Viral/metabolismo , Ensamble de Virus , Internalización del Virus , Secuencia de Aminoácidos , Cristalografía por Rayos X , Glicoproteínas/química , Glicoproteínas/genética , Orthohantavirus/genética , Orthohantavirus/fisiología , Concentración de Iones de Hidrógeno , Fusión de Membrana , Modelos Moleculares , Conformación Proteica , Multimerización de Proteína , Estabilidad Proteica , Homología de Secuencia de Aminoácido , Temperatura , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/genética

RESUMEN

The envelope (E) protein from Dengue and Zika viruses comprises three functional and structural domains (DI, DII, and DIII). Domain III induces most of the neutralizing antibodies and, as such, is considered as having the highest antigenic potential for the evaluation of population-level surveillance and for detecting past infections in both Dengue and Zika patients. The present study aimed to clone and express recombinant proteins of domain III from Dengue virus serotype 2 and from Zika virus in a prokaryotic system, as well as evaluate their immunogenicity and cross-reactivity. Both antigens were successfully purified and their antigenicity was assessed in mice. The antibodies elicited by domain III of Zika and Dengue virus antigens recognized specifically the native proteins in infected cells. Furthermore, the antigens showed a more specific immunogenic response than that of domain III proteins from Dengue virus. The generated recombinant proteins can be potentially used in subunit vaccines or for surveillance studies.

Asunto(s)

Virus del Dengue/genética , Proteínas del Envoltorio Viral/genética , Proteínas del Envoltorio Viral/aislamiento & purificación , Virus Zika/genética , Animales , Anticuerpos Antivirales/inmunología , Reacciones Cruzadas , Dengue/inmunología , Dengue/prevención & control , Dengue/virología , Vacunas contra el Dengue , Virus del Dengue/química , Virus del Dengue/inmunología , Femenino , Expresión Génica , Humanos , Ratones , Ratones Endogámicos BALB C , Dominios Proteicos , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/inmunología , Vacunas Virales/química , Vacunas Virales/genética , Vacunas Virales/inmunología , Vacunas Virales/aislamiento & purificación , Virus Zika/química , Virus Zika/inmunología , Infección por el Virus Zika/inmunología , Infección por el Virus Zika/prevención & control , Infección por el Virus Zika/virología

RESUMEN

BACKGROUND: At the present time, dengue is one of the most important arboviruses affecting man, becoming a serious global public health problem, especially in subtropical and tropical countries, where environmental conditions favor the development and proliferation of the mosquito Aedes aegypti. Dengue is caused by a type of flavivírus, which is an enveloped virus of spherical geometry. Nowadays, it is one of the diseases with the highest incidence in Brazil, reaching the population of all states, regardless of social class. Several papers address the molecular aspects of infection of human cell by the viruses, which are reviewed in this work. CONCLUSION: Analyzing the three-dimensional structures of the fusion peptide of dengue virus protein E, we observed that the fusion peptide presents a region rich in hydrophobic residues and a "collar" of charged, polar residues. Probably, this hydrophilic collar plays an important role in the fusion process between the dengue virus and the cell membrane. In order for this disease to cease being a serious global public health problem, we must deepen our knowledge about the fusion process between the dengue virus and the cell membrane through further experimental and, especially, computational studies to find ways to inhibit the mechanism of virus infection.

Asunto(s)

Virus del Dengue/fisiología , Virus del Dengue/ultraestructura , Proteínas del Envoltorio Viral/química , Internalización del Virus , Dengue/virología , Virus del Dengue/química , Virus del Dengue/patogenicidad , Interacciones Huésped-Patógeno/fisiología , Humanos , Simulación de Dinámica Molecular , Proteínas del Envoltorio Viral/metabolismo

RESUMEN

The envelope glycoprotein 51 (gp51) is essential for bovine leukaemia virus (BLV) entry to bovine B-lymphocytes. Although the bovine adaptor protein 3 complex subunit delta-1 (boAP3D1) has been proposed as the potential receptor, the specific ligand-receptor interaction has not yet been completely defined and boAP3D1 receptor and gp51 3D structures have not been determined. This study was thus aimed at a functional annotation of boAP3D1 cellular adaptor protein and BLV gp51 and, proposing a reliable model for gp51-AP3D1 interaction using bioinformatics tools. The boAP3D1 receptor interaction patterns were calculated based on models of boAP3D1 receptor and gp51 complexes' 3D structures, which were constructed using homology techniques and data-driven docking strategy. The results showed that the participation of 6 key amino acids (aa) on gp51 (Asn170, Trp127, His115, Ala97, Ser98 and Glu128) and 4 aa on AP3D1 (Lys925, Asp807, Asp695 and Arg800) was highly probable in the interaction between gp51 and BLVR domains. Three gp51 recombinant peptides were expressed and purified to validate these results: the complete domain (rgp51), the N-terminal portion (rNgp51) and the C-terminal fragment (rCgp51); and binding assays to Madin-Darby bovine kidney (MDBK) cells were then carried out with each recombinant. It was found that rNgp51 preferentially bound to MDBK cells, suggesting this domain's functional role during invasion. The rNgp51-MDBK cell interaction was sensitive to trypsin (98% reduction) and chymotrypsin treatment (80% reduction). These results highlighted that the N-terminal portion of gp51 interacted in vitro with the AP3D1 receptor and provides a plausible in silico interaction model.

Asunto(s)

Subunidades delta de Complexo de Proteína Adaptadora/metabolismo , Simulación por Computador , Virus de la Leucemia Bovina/metabolismo , Proteínas del Envoltorio Viral/metabolismo , Subunidades delta de Complexo de Proteína Adaptadora/química , Secuencia de Aminoácidos , Animales , Bovinos , Línea Celular , Interacciones Hidrofóbicas e Hidrofílicas , Simulación del Acoplamiento Molecular , Anotación de Secuencia Molecular , Unión Proteica , Mapeo de Interacción de Proteínas , Estructura Secundaria de Proteína , Proteínas Recombinantes/metabolismo , Reproducibilidad de los Resultados , Termodinámica , Proteínas del Envoltorio Viral/química