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Vaccines Jun 2024T help (Th), stimulation of toll-like receptors (pathogen-associated molecular patterns, PAMPs), and antigen organization and repetitiveness (pathogen-associated...
Identifying Key Drivers of Efficient B Cell Responses: On the Role of T Help, Antigen-Organization, and Toll-like Receptor Stimulation for Generating a Neutralizing Anti-Dengue Virus Response.
T help (Th), stimulation of toll-like receptors (pathogen-associated molecular patterns, PAMPs), and antigen organization and repetitiveness (pathogen-associated structural patterns, PASPs) were shown numerous times to be important in driving B-cell and antibody responses. In this study, we dissected the individual contributions of these parameters using newly developed "Immune-tag" technology. As model antigens, we used eGFP and the third domain of the dengue virus 1 envelope protein (DV1 EDIII), the major target of virus-neutralizing antibodies. The respective proteins were expressed alone or genetically fused to the N-terminal fragment of the cucumber mosaic virus (CMV) capsid protein-nCMV, rendering the antigens oligomeric. In a step-by-step manner, RNA was attached as a PAMP, and/or a universal Th-cell epitope was genetically added for additional Th. Finally, a PASP was added to the constructs by displaying the antigens highly organized and repetitively on the surface of CMV-derived virus-like particles (CuMV VLPs). Sera from immunized mice demonstrated that each component contributed stepwise to the immunogenicity of both proteins. All components combined in the CuMV VLP platform induced by far the highest antibody responses. In addition, the DV1 EDIII induced high levels of DENV-1-neutralizing antibodies only if displayed on VLPs. Thus, combining multiple cues typically associated with viruses results in optimal antibody responses.
PubMed: 38932390
DOI: 10.3390/vaccines12060661 -
Vaccines May 2024The dengue virus, the primary cause of dengue fever, dengue hemorrhagic fever, and dengue shock syndrome, is the most widespread mosquito-borne virus worldwide. In...
The dengue virus, the primary cause of dengue fever, dengue hemorrhagic fever, and dengue shock syndrome, is the most widespread mosquito-borne virus worldwide. In recent decades, the prevalence of dengue fever has increased markedly, presenting substantial public health challenges. Consequently, the development of an efficacious vaccine against dengue remains a critical goal for mitigating its spread. Our research utilized Celcradle™, an innovative tidal bioreactor optimized for high-density cell cultures, to grow Vero cells for dengue virus production. By maintaining optimal pH levels (7.0 to 7.4) and glucose concentrations (1.5 g/L to 3.5 g/L) during the proliferation of cells and viruses, we achieved a peak Vero cell count of approximately 2.46 × 10, nearly ten times the initial count. The use of Celcradle™ substantially decreased the time required for cell yield and virus production compared to conventional Petri dish methods. Moreover, our evaluation of the immunogenicity of the Celcradle™-produced inactivated DENV4 through immunization of mice revealed that sera from these mice demonstrated cross-reactivity with DENV4 cultured in Petri dishes and showed elevated antibody titers compared to those from mice immunized with virus from Petri dishes. These results indicate that the dengue virus cultivated using the Celcradle™ system exhibited enhanced immunogenicity relative to that produced in traditional methods. In conclusion, our study highlights the potential of the Celcradle™ bioreactor for large-scale production of inactivated dengue virus vaccines, offering significant promise for reducing the global impact of dengue virus infections and accelerating the development of effective vaccination strategies.
PubMed: 38932292
DOI: 10.3390/vaccines12060563 -
Viruses May 2024The complete lack of yellow fever virus (YFV) in Asia, and the lack of urban YFV transmission in South America, despite the abundance of the peridomestic mosquito vector...
The complete lack of yellow fever virus (YFV) in Asia, and the lack of urban YFV transmission in South America, despite the abundance of the peridomestic mosquito vector () is an enigma. An immunologically naïve population of over 2 billion resides in Asia, with most regions infested with the urban YF vector. One hypothesis for the lack of Asian YF, and absence of urban YF in the Americas for over 80 years, is that prior immunity to related flaviviruses like dengue (DENV) or Zika virus (ZIKV) modulates YFV infection and transmission dynamics. Here we utilized an interferon α/β receptor knock-out mouse model to determine the role of pre-existing dengue-2 (DENV-2) and Zika virus (ZIKV) immunity in YF virus infection, and to determine mechanisms of cross-protection. We utilized African and Brazilian YF strains and found that DENV-2 and ZIKV immunity significantly suppresses YFV viremia in mice, but may or may not protect relative to disease outcomes. Cross-protection appears to be mediated mainly by humoral immune responses. These studies underscore the importance of re-assessing the risks associated with YF outbreak while accounting for prior immunity from flaviviruses that are endemic.
Topics: Animals; Yellow Fever; Mice; Cross Protection; Disease Models, Animal; Yellow fever virus; Zika Virus; Mice, Knockout; Zika Virus Infection; Dengue Virus; Receptor, Interferon alpha-beta; Antibodies, Viral; Flavivirus; Aedes; Dengue; Female; Viremia; Mosquito Vectors; Flavivirus Infections; Mice, Inbred C57BL
PubMed: 38932129
DOI: 10.3390/v16060836 -
Microorganisms May 2024Dengue virus (DENV) poses a significant threat to global health, infecting approximately 390 million people annually. This virus comprises four serotypes capable of...
Dengue virus (DENV) poses a significant threat to global health, infecting approximately 390 million people annually. This virus comprises four serotypes capable of causing severe disease. Genetic analyses are crucial for understanding the epidemiology, evolution, and spread of DENV. Although previous studies have focused on the envelope protein-coding (E) gene, only a few primers can efficiently detect and amplify the viral genes from multiple endemic countries simultaneously. In this study, we designed degenerate primer pairs for each DENV serotype to amplify and sequence the entire E gene, using globally representative sequences for each serotype. These primers were validated using DENV isolates from various Asian countries and demonstrated broad-spectrum detection capabilities and high-quality sequences. The primers provide effective tools for genetic analysis in the regions affected by dengue, aiding strain identification and epidemiological studies during outbreaks.
PubMed: 38930474
DOI: 10.3390/microorganisms12061092 -
Evolution of STAT2 resistance to flavivirus NS5 occurred multiple times despite genetic constraints.Nature Communications Jun 2024Zika and dengue virus nonstructural protein 5 antagonism of STAT2, a critical interferon signaling transcription factor, to suppress the host interferon response is...
Zika and dengue virus nonstructural protein 5 antagonism of STAT2, a critical interferon signaling transcription factor, to suppress the host interferon response is required for viremia and pathogenesis in a vertebrate host. This affects viral species tropism, as mouse STAT2 resistance renders only immunocompromised or humanized STAT2 mice infectable. Here, we explore how STAT2 evolution impacts antagonism. By measuring the susceptibility of 38 diverse STAT2 proteins, we demonstrate that resistance arose numerous times in mammalian evolution. In four species, resistance requires distinct sets of multiple amino acid changes that often individually disrupt STAT2 signaling. This reflects an evolutionary ridge where progressive resistance is balanced by the need to maintain STAT2 function. Furthermore, resistance may come with a fitness cost, as resistance that arose early in lemur evolution was subsequently lost in some lemur lineages. These findings underscore that while it is possible to evolve resistance to antagonism, complex evolutionary trajectories are required to avoid detrimental host fitness consequences.
Topics: STAT2 Transcription Factor; Animals; Viral Nonstructural Proteins; Evolution, Molecular; Humans; Mice; Dengue Virus; Zika Virus; Flavivirus; Phylogeny; Host-Pathogen Interactions
PubMed: 38926343
DOI: 10.1038/s41467-024-49758-0 -
Journal of Vector Borne Diseases Apr 2024In Port Blair, the capital of Andaman & Nicobar Islands, in the Bay of Bengal, India, there was a sudden increase in fever cases resembling the symptoms of dengue in the...
BACKGROUND OBJECTIVES
In Port Blair, the capital of Andaman & Nicobar Islands, in the Bay of Bengal, India, there was a sudden increase in fever cases resembling the symptoms of dengue in the monsoon period of 2022. Hence, an investigation was carried out to find out epidemiological and entomological reasons behind the outbreak.
METHODS
An entomological survey was carried out in 24 wards of Port Blair Municipal Council (PBMC) area, epidemiological data of last six years (January-December 2017-2021 and January-October 2022) and patient details of the year 2022 were collected. Both the epidemiological and entomological data were analyzed concerning time and place.
RESULTS
During this outbreak period tyres (22.4%) came out as a major breeding habitat followed by small discarded materials (17.5%), metal drums (15.3%), and plastic drums (11.7%). In rainy season, peri-domestic breeding (55%) was more than the domestic breeding (45%) habitat. Ae. aegypti had a high preference for indoor large containers (100-1000 L) like plastic tank, metal drum and cement tank whereasAe. albopictus prefers to breed in medium sized plastic container (20-100 L) and outdoor water receptacles like tyres, flower pots, and domestic discarded materials.
INTERPRETATION CONCLUSION
By source reduction, indoor space spray and outdoor fogging, vector density was controlled which curtailed the transmission and within eight weeks a decreasing trend of dengue cases was noticed. A regular entomological survey is crucial to know the seasonality and key breeding habitats of the vector for proper planning of vector control.
Topics: India; Dengue; Animals; Humans; Disease Outbreaks; Aedes; Mosquito Vectors; Seasons; Ecosystem; Female; Male; Adult; Adolescent; Young Adult; Child; Middle Aged; Islands; Dengue Virus; Child, Preschool
PubMed: 38922656
DOI: 10.4103/jvbd.jvbd_144_23 -
In silico screening of potential plant peptides against the non-structural proteins of dengue virus.Journal of Vector Borne Diseases Apr 2024Peptides isolated from different sources of plants have the advantages of specificity, lower toxicity, and increased therapeutic effects; hence, it is necessary to...
BACKGROUND OBJECTIVES
Peptides isolated from different sources of plants have the advantages of specificity, lower toxicity, and increased therapeutic effects; hence, it is necessary to search for newer antivirals from plant sources for the treatment of dengue viral infections.
METHODS
In silico screening of selected plant peptides against the non-structural protein 1, NS3 protease domain (NS2B-NS3Pro) with the cofactor and ATPase/helicase domain (NS3 helicase domain/NS3hel) of dengue virus was performed. The physicochemical characteristics of the peptides were calculated using Protparam tools, and the allergenicity and toxicity profiles were assessed using allergenFP and ToxinPred, respectively.
RESULTS
Among the tested compounds, Ginkbilobin demonstrated higher binding energy against three tested nonstructural protein targets. Kalata B8 demonstrated maximum binding energy against NSP-1 and NSP-2, whereas Circulin A acted against the NSP3 protein of dengue virus.
INTERPRETATION CONCLUSION
The three compounds identified by in silico screening can be tested in vitro, which could act as potential leads as they are involved in hampering the replication of the dengue virus by interacting with the three prime non-structural proteins.
Topics: Viral Nonstructural Proteins; Dengue Virus; Antiviral Agents; Computer Simulation; Peptides; Plant Proteins; Molecular Docking Simulation; Serine Endopeptidases; RNA Helicases; Viral Proteases
PubMed: 38922655
DOI: 10.4103/jvbd.jvbd_47_23 -
Journal of Vector Borne Diseases Apr 2024The incidence of Dengue Hemorrhagic Fever (DHF) continues to increase over time in the world, including Indonesia. One of the prevention efforts against dengue virus...
BACKGROUND OBJECTIVES
The incidence of Dengue Hemorrhagic Fever (DHF) continues to increase over time in the world, including Indonesia. One of the prevention efforts against dengue virus transmission is to avoid vector mosquito bites by the use of repellants. Using repellents can reduce exposure to mosquito bites that may cause infection with the dengue virus. This study aimed to determine the effectiveness of repellent lotion composed of patchouli batik extract (Pogostemon cablin) from Southeast Sulawesi varieties against Aedes aegypti mosquitoes.
METHODS
The research subjects were Aedes aegypti adult mosquitoes. The research consisted of three stages. The first stage was a phytochemical test (qualitative method), the second stage was the analysis of patchouli essential oil (GC-MS method) and the third stage was a test of the effectiveness of lotions made from patchouli extract in lotion preparations against Aedes aegypti.
RESULTS
The results of the effectiveness test of patchouli leaf repellent (Pogestemon cablin) lotion preparations were as follows: for a concentration of 2.5%, protective power 81.5%; concentration 5%, protection power 83.67%; concentration 7.5%, protection power 88.64 %; the concentration of 10%, protection power 90.44%, and the concentration of 12.5% had protection power 90.89%. Probit analysis and linear regression showed the value of ProbitLc 50 was 6.631.
INTERPRETATION CONCLUSION
The results of the effectiveness test of Pogestemon cablin repellent lotion preparations with the most effective concentrations were 10% and 12.5%. The results of ANOVA test indicated there was no difference in the average value of the protection power in patchouli leaves.
Topics: Animals; Aedes; Insect Repellents; Pogostemon; Indonesia; Plant Extracts; Oils, Volatile; Female; Mosquito Vectors; Plant Leaves; Gas Chromatography-Mass Spectrometry
PubMed: 38922650
DOI: 10.4103/jvbd.jvbd_38_22 -
Pathogens (Basel, Switzerland) Jun 2024(OROV) is an arbovirus transmitted by midges that has been involved in outbreaks throughout Central and South America. In Brazil, human cases have been historically...
(OROV) is an arbovirus transmitted by midges that has been involved in outbreaks throughout Central and South America. In Brazil, human cases have been historically concentrated in the northern region of the country. Oropouche fever in humans range from mild clinical signs to rare neurological events, and is considered a neglected tropical disease in Brazil. Due to the clinical similarities to other arboviruses, such as chikungunya and dengue viruses, OROV infections are likely to be underreported. Chikungunya virus (CHIKV) cases in Brazil were first recognized in 2014 in the states of Amapá and Bahia in the north and northeast regions, respectively. Both OROV and CHIKV cause nonspecific symptoms, making clinical diagnosis difficult in a scenario of arbovirus cocirculation. Aiming to investigate OROV transmission during the CHIKV introduction in the state of Amapá located in the Brazilian Amazon, we conducted a retrospective molecular (RT-qPCR) and serological investigation in febrile cases (N = 166) collected between August 2014 and May 2015. All acute serum samples were negative for OROV RNA using RT-qPCR. However, neutralizing antibodies for OROV were detected using a plaque reduction neutralization test (PRNT) in 10.24% (17/166) of the patients, with neutralizing antibody titers ranging from 20 to ≥640, suggesting the previous exposure of patients to OROV. Regarding CHIKV, recent exposure was confirmed by the detection of CHIKV RNA in 20.25% (33/163) of the patients and by the detection of anti-CHIKV IgM in 28.57% (44/154) of the patients. The additional detection of anti-CHIKV IgG in 12.58% (19/151) of the febrile patients suggests that some individuals had been previously exposed to CHIKV. Whether the OROV exposure reported here occurred prior or during the CHIKV circulation in Amapá, is unknown, but because those arboviral infections share similar clinical signs and symptoms, a silent circulation of enzootic arboviruses during the introduction of exotic arboviruses may occur, and highlights the importance of syndromic cases' surveillance to arboviruses in Brazil.
PubMed: 38921767
DOI: 10.3390/pathogens13060469 -
Pathogens (Basel, Switzerland) May 2024The Chikungunya virus (CHIKV) presents global health challenges, with Brazil experiencing outbreaks since its introduction in 2014. In 2023, following a CHIKV outbreak...
The Chikungunya virus (CHIKV) presents global health challenges, with Brazil experiencing outbreaks since its introduction in 2014. In 2023, following a CHIKV outbreak in Minas Gerais (MG), social media was used to optimize an entomological survey aimed at identifying vectors and viral lineages and assessing insecticide resistance. Following Instagram posts, residents with suspected CHIKV infection were able to schedule mosquito aspirations. In total, 421 mosquitoes (165 and 256 ) were captured from 40 households in Salinas city (MG) and tested for the Dengue, Zika, and Chikungunya viruses through RT-qPCR. Twelve of 57 pools (10 and two ) tested positive for CHIKV RNA. Viral RNA was also detected in the heads of nine , indicating viral dissemination but not in . Genome sequencing yielded the first near-complete genome from the 2023 outbreak, unveiling that the CHIKV strain belonged to the East/Central/South African (ECSA) genotype. Additionally, genetic analyses revealed high frequencies of alleles, including in CHIKV-infected mosquitoes, suggesting resistance to pyrethroid insecticides in this population. Social media was important for guiding mosquito-capture efforts in CHIKV transmission hotspots, thus optimizing the opportunity for viral detection. These findings emphasize the urgent need for innovative vector studies and control strategies, as well as interdisciplinary approaches in public health interventions.
PubMed: 38921757
DOI: 10.3390/pathogens13060457