Enzyme-Linked Immunosorbent Assay Using Henipavirus-Receptor EphrinB2 and Monoclonal Antibodies for Detecting Nipah and Hendra Viruses.

The Nipah virus (NiV) and the Hendra virus (HeV) are highly pathogenic zoonotic diseases that can cause fatal infections in humans and animals. Early detection is critical for the control of NiV and HeV infections. We present the development of two antigen-detection ELISAs (AgELISAs) using the henipavirus-receptor EphrinB2 and monoclonal antibodies (mAbs) to detect NiV and HeV. The NiV AgELISA detected only NiV, whereas the NiV/HeV AgELISA detected both NiV and HeV. The diagnostic specificities of the NiV AgELISA and the NiV/HeV AgELISA were 100% and 97.8%, respectively. Both assays were specific for henipaviruses and showed no cross-reactivity with other viruses. The AgELISAs detected NiV antigen in experimental pig nasal wash samples taken at 4 days post-infection. With the combination of both AgELISAs, NiV can be differentiated from HeV. Complementing other henipavirus detection methods, these two newly developed AgELISAs can rapidly detect NiV and HeV in a large number of samples and are suitable for use in remote areas where other tests are not available.

Research on emerging infectious diseases: pros and cons of centralised government controls.

As the world grapples with the constant threat of new pathogens, the role of government oversight in research and response efforts has become a topic of considerable debate in the academic community. In the recently released "SOP [standard operating procedure] for Nipah virus research in Kerala for studies involving human participants / human samples" by the Government of Kerala, the SOP, apart from administrative permission, requires the proposal to be cleared by the Institutional Research Committee at a Government Medical College, and the inclusion of an investigator from a government institution [1]. In these challenging times, it is crucial to weigh the pros and cons of stringent administrative controls to ensure an effective and ethical approach to tackling emerging infectious diseases.

Multi-epitope vaccine design using in silico analysis of glycoprotein and nucleocapsid of NIPAH virus.

According to the 2018 WHO R&D Blueprint, Nipah virus (NiV) is a priority disease, and the development of a vaccine against NiV is strongly encouraged. According to criteria used to categorize zoonotic diseases, NiV is a stage III disease that can spread to people and cause unpredictable outbreaks. Since 2001, the NiV virus has caused annual outbreaks in Bangladesh, while in India it has caused occasional outbreaks. According to estimates, the mortality rate for infected individuals ranges from 70 to 91%. Using immunoinformatic approaches to anticipate the epitopes of the MHC-I, MHC-II, and B-cells, they were predicted using the NiV glycoprotein and nucleocapsid protein. The selected epitopes were used to develop a multi-epitope vaccine construct connected with linkers and adjuvants in order to improve immune responses to the vaccine construct. The 3D structure of the engineered vaccine was anticipated, optimized, and confirmed using a variety of computer simulation techniques so that its stability could be assessed. According to the immunological simulation tests, it was found that the vaccination elicits a targeted immune response against the NiV. Docking with TLR-3, 7, and 8 revealed that vaccine candidates had high binding affinities and low binding energies. Finally, molecular dynamic analysis confirms the stability of the new vaccine. Codon optimization and in silico cloning showed that the proposed vaccine was expressed to a high degree in Escherichia coli. The study will help in identifying a potential epitope for a vaccine candidate against NiV. The developed multi-epitope vaccine construct has a lot of potential, but they still need to be verified by in vitro & in vivo studies.

A potent Henipavirus cross-neutralizing antibody reveals a dynamic fusion-triggering pattern of the G-tetramer.

The Hendra and Nipah viruses (HNVs) are highly pathogenic pathogens without approved interventions for human use. In addition, the interaction pattern between the attachment (G) and fusion (F) glycoproteins required for virus entry remains unclear. Here, we isolate a panel of Macaca-derived G-specific antibodies that cross-neutralize HNVs via multiple mechanisms. The most potent antibody, 1E5, confers adequate protection against the Nipah virus challenge in female hamsters. Crystallography demonstrates that 1E5 has a highly similar binding pattern to the receptor. In cryo-electron microscopy studies, the tendency of 1E5 to bind to the upper or lower heads results in two distinct quaternary structures of G. Furthermore, we identify the extended outer loop ß1S2-ß1S3 of G and two pockets on the apical region of fusion (F) glycoprotein as the essential sites for G-F interactions. This work highlights promising drug candidates against HNVs and contributes deeper insights into the viruses.

Nipah Virus Neurotropism: Insights into Blood-Brain Barrier Disruption.

The genome of the Nipah virus (NiV) encodes a variety of structural proteins linked to a diverse array of symptoms, including fevers, headaches, somnolence, and respiratory impairment. In instances of heightened severity, it can also invade the central nervous system (CNS), resulting in more pronounced problems. This work investigates the effects of NiV on the blood-brain barrier (BBB), the vital physiological layer responsible for safeguarding the CNS by regulating the passage of chemicals into the brain selectively. To achieve this, the researchers (MMJAO, AM and MNMD) searched a variety of databases for relevant articles on NiV and BBB disruption, looking for evidence of work on inflammation, immune response (cytokines and chemokines), tight junctions (TJs), and basement membranes related to NiV and BBB. Based on these works, it appears that the affinity of NiV for various receptors, including Ephrin-B2 and Ephrin-B3, has seen many NiV infections begin in the respiratory epithelium, resulting in the development of acute respiratory distress syndrome. The virus then gains entry into the circulatory system, offering it the potential to invade brain endothelial cells (ECs). NiV also has the ability to infect the leukocytes and the olfactory pathway, offering it a "Trojan horse" strategy. When NiV causes encephalitis, the CNS generates a strong inflammatory response, which makes the blood vessels more permeable. Chemokines and cytokines all have a substantial influence on BBB disruption, and NiV also has the ability to affect TJs, leading to disturbances in the structural integrity of the BBB. The pathogen's versatility is also shown by its capacity to impact multiple organ systems, despite particular emphasis on the CNS. It is of the utmost importance to comprehend the mechanisms by which NiV impacts the integrity of the BBB, as such comprehension has the potential to inform treatment approaches for NiV and other developing viral diseases. Nevertheless, the complicated pathophysiology and molecular pathways implicated in this phenomenon have offered several difficult challenges to researchers to date, underscoring the need for sustained scientific investigation and collaboration in the ongoing battle against this powerful virus.

Evaluation of the immunogenicity of an mRNA vectored Nipah virus vaccine candidate in pigs.

Nipah virus (NiV) poses a significant threat to human and livestock populations across South and Southeast Asia. Vaccines are required to reduce the risk and impact of spillover infection events. Pigs can act as an intermediate amplifying host for NiV and, separately, provide a preclinical model for evaluating human vaccine candidate immunogenicity. The aim of this study was therefore to evaluate the immunogenicity of an mRNA vectored NiV vaccine candidate in pigs. Pigs were immunized twice with 100 µg nucleoside-modified mRNA vaccine encoding soluble G glycoprotein from the Malaysia strain of NiV, formulated in lipid nanoparticles. Potent antigen-binding and virus neutralizing antibodies were detected in serum following the booster immunization. Antibody responses effectively neutralized both the Malaysia and Bangladesh strains of NiV but showed limited neutralization of the related (about 80% amino acid sequence identity for G) Hendra virus. Antibodies were also capable of neutralizing NiV glycoprotein mediated cell-cell fusion. NiV G-specific T cell cytokine responses were also measurable following the booster immunization with evidence for induction of both CD4 and CD8 T cell responses. These data support the further evaluation of mRNA vectored NiV G as a vaccine for both pigs and humans.

Therapeutic administration of a cross-reactive mAb targeting the fusion glycoprotein of Nipah virus protects nonhuman primates.

No licensed vaccines or therapies exist for patients infected with Nipah virus (NiV), although an experimental human monoclonal antibody (mAb) cross-reactive to the NiV and Hendra virus (HeV) G glycoprotein, m102.4, has been tested in a phase 1 trial and has been provided under compassionate use for both HeV and NiV exposures. NiV is a highly pathogenic zoonotic paramyxovirus causing regular outbreaks in humans and animals in South and Southeast Asia. The mortality rate of NiV infection in humans ranges from 40% to more than 90%, making it a substantial public health concern. The NiV G glycoprotein mediates host cell attachment, and the F glycoprotein facilitates membrane fusion and infection. We hypothesized that a mAb against the prefusion conformation of the F glycoprotein may confer better protection than m102.4. To test this, two potent neutralizing mAbs against NiV F protein, hu1F5 and hu12B2, were compared in a hamster model. Hu1F5 provided superior protection to hu12B2 and was selected for comparison with m102.4 for the ability to protect African green monkeys (AGMs) from a stringent NiV challenge. AGMs were exposed intranasally to the Bangladesh strain of NiV and treated 5 days after exposure with either mAb (25 milligrams per kilogram). Whereas only one of six AGMs treated with m102.4 survived until the study end point, all six AGMs treated with hu1F5 were protected. Furthermore, a reduced 10 milligrams per kilogram dose of hu1F5 also provided complete protection against NiV challenge, supporting the upcoming clinical advancement of this mAb for postexposure prophylaxis and therapy.

Potent human neutralizing antibodies against Nipah virus derived from two ancestral antibody heavy chains.

Nipah virus (NiV) is a World Health Organization priority pathogen and there are currently no approved drugs for clinical immunotherapy. Through the use of a naïve human phage-displayed Fab library, two neutralizing antibodies (NiV41 and NiV42) targeting the NiV receptor binding protein (RBP) were identified. Following affinity maturation, antibodies derived from NiV41 display cross-reactivity against both NiV and Hendra virus (HeV), whereas the antibody based on NiV42 is only specific to NiV. Results of immunogenetic analysis reveal a correlation between the maturation of antibodies and their antiviral activity. In vivo testing of NiV41 and its mature form (41-6) show protective efficacy against a lethal NiV challenge in hamsters. Furthermore, a 2.88 Å Cryo-EM structure of the tetrameric RBP and antibody complex demonstrates that 41-6 blocks the receptor binding interface. These findings can be beneficial for the development of antiviral drugs and the design of vaccines with broad spectrum against henipaviruses.

Structure and design of Langya virus glycoprotein antigens.

Langya virus (LayV) is a recently discovered henipavirus (HNV), isolated from febrile patients in China. HNV entry into host cells is mediated by the attachment (G) and fusion (F) glycoproteins which are the main targets of neutralizing antibodies. We show here that the LayV F and G glycoproteins promote membrane fusion with human, mouse, and hamster target cells using a different, yet unknown, receptor than Nipah virus (NiV) and Hendra virus (HeV) and that NiV- and HeV-elicited monoclonal and polyclonal antibodies do not cross-react with LayV F and G. We determined cryoelectron microscopy structures of LayV F, in the prefusion and postfusion states, and of LayV G, revealing their conformational landscape and distinct antigenicity relative to NiV and HeV. We computationally designed stabilized LayV G constructs and demonstrate the generalizability of an HNV F prefusion-stabilization strategy. Our data will support the development of vaccines and therapeutics against LayV and closely related HNVs.

Interaction of Nipah Virus F and G with the Cellular Protein Cortactin Discovered by a Proximity Interactome Assay.

Nipah virus (NiV) is a highly lethal zoonotic virus with a potential large-scale outbreak, which poses a great threat to world health and security. In order to explore more potential factors associated with NiV, a proximity labeling method was applied to investigate the F, G, and host protein interactions systematically. We screened 1996 and 1524 high-confidence host proteins that interacted with the NiV fusion (F) glycoprotein and attachment (G) glycoprotein in HEK293T cells by proximity labeling technology, and 863 of them interacted with both F and G. The results of GO and KEGG enrichment analysis showed that most of these host proteins were involved in cellular processes, molecular binding, endocytosis, tight junction, and other functions. Cytoscape software (v3.9.1) was used for visual analysis, and the results showed that Cortactin (CTTN), Serpine mRNA binding protein 1 (SERBP1), and stathmin 1 (STMN1) were the top 20 proteins and interacted with F and G, and were selected for further validation. We observed colocalization of F-CTTN, F-SERBP1, F-STMN1, G-CTTN, G-SERBP1, and G-STMN1 using confocal fluorescence microscopy, and the results showed that CTTN, SERBP1, and STMN1 overlapped with NiV F and NiV G in HEK293T cells. Further studies found that CTTN can significantly inhibit the infection of the Nipah pseudovirus (NiVpv) into host cells, while SERBP1 and STMN1 had no significant effect on pseudovirus infection. In addition, CTTN can also inhibit the infection of the Hendra pseudovirus (HeVpv) in 293T cells. In summary, this study revealed that the potential host proteins interacted with NiV F and G and demonstrated that CTTN could inhibit NiVpv and HeVpv infection, providing new evidence and targets for the study of drugs against these diseases.

Infection and transmission of henipavirus in animals.

Henipavirus (HNV) is well known for two zoonotic viruses in the genus, Hendra virus (HeV) and Nipah virus (NiV), which pose serious threat to human and animal health. In August 2022, a third zoonotic virus in the genus Henipavirus, Langya virus (LayV), was discovered in China. The emergence of HeV, NiV, and LayV highlights the persistent threat of HNV to human and animal health. In addition to the above three HNVs, new species within this genus are still being discovered. Although they have not yet caused a pandemic in humans or livestock, they still have the risk of spillover as a potential threat to the health of humans and animals. It's important to understand the infection and transmission of different HNV in animals for the prevention and control of current or future HNV epidemics. Therefore, this review mainly summarizes the animal origin, animal infection and transmission of HNV that have been found worldwide, and further analyzes and summarizes the rules of infection and transmission, so as to provide a reference for relevant scientific researchers. Furthermore, it can provide a direction for epidemic prevention and control, and animal surveillance to reduce the risk of the global pandemic of HNV.

Clinico-epidemiological presentations and management of Nipah virus infection during the outbreak in Kozhikode district, Kerala state, India 2023.

India experienced its sixth Nipah virus (NiV) outbreak in September 2023 in the Kozhikode district of Kerala state. The NiV is primarily transmitted by spillover events from infected bats followed by human-to-human transmission. The clinical specimens were screened using real-time RT-PCR, and positive specimens were further characterized using next-generation sequencing. We describe here an in-depth clinical presentation and management of NiV-confirmed cases and outbreak containment activities. The current outbreak reported a total of six cases with two deaths, with a case fatality ratio of 33.33%. The cases had a mixed presentation of acute respiratory distress syndrome and encephalitis syndrome. Fever was a persistent presentation in all the cases. The Nipah viral RNA was detected in clinical specimens until the post-onset day of illness (POD) 14, with viral load in the range of 1.7-3.3 × 104 viral RNA copies/mL. The genomic analysis showed that the sequences from the current outbreak clustered into the Indian clade similar to the 2018 and 2019 outbreaks. This study highlights the vigilance of the health system to detect and effectively manage the clustering of cases with clinical presentations similar to NiV, which led to early detection and containment activities.

Structure-guided mutagenesis of Henipavirus receptor-binding proteins reveals molecular determinants of receptor usage and antibody-binding epitopes.

Nipah virus (NiV) is a highly lethal, zoonotic Henipavirus (HNV) that causes respiratory and neurological signs and symptoms in humans. Similar to other paramyxoviruses, HNVs mediate entry into host cells through the concerted actions of two surface glycoproteins: a receptor-binding protein (RBP) that mediates attachment and a fusion glycoprotein (F) that triggers fusion in an RBP-dependent manner. NiV uses ephrin-B2 (EFNB2) and ephrin-B3 (EFNB3) as entry receptors. Ghana virus (GhV), a novel HNV identified in a Ghanaian bat, uses EFNB2 but not EFNB3. In this study, we employ a structure-informed approach to identify receptor-interfacing residues and systematically introduce GhV-RBP residues into a NiV-RBP backbone to uncover the molecular determinants of EFNB3 usage. We reveal two regions that severely impair EFNB3 binding by NiV-RBP and EFNB3-mediated entry by NiV pseudotyped viral particles. Further analyses uncovered two-point mutations (NiVN557SGhV and NiVY581TGhV) pivotal for this phenotype. Moreover, we identify NiV interaction with Y120 of EFNB3 as important for the usage of this receptor. Beyond these EFNB3-related findings, we reveal two domains that restrict GhV binding of EFNB2, confirm the HNV-head as an immunodominant target for polyclonal and monoclonal antibodies, and describe putative epitopes for GhV- and NiV-specific monoclonal antibodies. Cumulatively, the work presented here generates useful reagents and tools that shed insight to residues important for NiV usage of EFNB3, reveal regions critical for GhV binding of EFNB2, and describe putative HNV antibody-binding epitopes. IMPORTANCE: Hendra virus and Nipah virus (NiV) are lethal, zoonotic Henipaviruses (HNVs) that cause respiratory and neurological clinical features in humans. Since their initial outbreaks in the 1990s, several novel HNVs have been discovered worldwide, including Ghana virus. Additionally, there is serological evidence of zoonotic transmission, lending way to concerns about future outbreaks. HNV infection of cells is mediated by the receptor-binding protein (RBP) and the Fusion protein (F). The work presented here identifies NiV RBP amino acids important for the usage of ephrin-B3 (EFNB3), a receptor highly expressed in neurons and predicted to be important for neurological clinical features caused by NiV. This study also characterizes epitopes recognized by antibodies against divergent HNV RBPs. Together, this sheds insight to amino acids critical for HNV receptor usage and antibody binding, which is valuable for future studies investigating determinants of viral pathogenesis and developing antibody therapies.

Novel methods for the rapid and sensitive detection of Nipah virus based on a CRISPR/Cas12a system.

Nipah virus (NiV), a bat-borne zoonotic viral pathogen with high infectivity and lethality to humans, has caused severe outbreaks in several countries of Asia during the past two decades. Because of the worldwide distribution of the NiV natural reservoir, fruit bats, and lack of effective treatments or vaccines for NiV, routine surveillance and early detection are the key measures for containing NiV outbreaks and reducing its influence. In this study, we developed two rapid, sensitive and easy-to-conduct methods, RAA-CRISPR/Cas12a-FQ and RAA-CRISPR/Cas12a-FB, for NiV detection based on a recombinase-aided amplification (RAA) assay and a CRISPR/Cas12a system by utilizing dual-labeled fluorophore-quencher or fluorophore-biotin ssDNA probes. These two methods can be completed in 45 min and 55 min and achieve a limit of detection of 10 copies per µL and 100 copies per µL of NiV N DNA, respectively. In addition, they do not cross-react with nontarget nucleic acids extracted from the pathogens causing similar symptoms to NiV, showing high specificity for NiV N DNA detection. Meanwhile, they show satisfactory performance in the detection of spiked samples from pigs and humans. Collectively, the RAA-CRISPR/Cas12a-FQ and RAA-CRISPR/Cas12a-FB methods developed by us would be promising candidates for the early detection and routine surveillance of NiV in resource-poor areas and outdoors.

Updated Insights into the Phylogenetics, Phylodynamics, and Genetic Diversity of Nipah Virus (NiV).

Nipah virus (NiV), a biosafety level 4 agent, was first identified in human clinical cases during an outbreak in 1998 in Malaysia and Singapore. While flying foxes are the primary host and viral vector, the infection is associated with a severe clinical presentation in humans, resulting in a high mortality rate. Therefore, NiV is considered a virus with an elevated epidemic potential which is further underscored by its recent emergence (September 2023) as an outbreak in India. Given the situation, it is paramount to understand the molecular dynamics of the virus to shed more light on its evolution and prevent potential future outbreaks. In this study, we conducted Bayesian phylogenetic analysis on all available NiV complete genomes, including partial N-gene NiV sequences (≥1000 bp) in public databases since the first human case, registered in 1998. We observed the distribution of genomes into three main clades corresponding to the genotypes Malaysia, Bangladesh and India, with the Malaysian clade being the oldest in evolutionary terms. The Bayesian skyline plot showed a recent increase in the viral population size since 2019. Protein analysis showed the presence of specific protein families (Hendra_C) in bats that might keep the infection in an asymptomatic state in bats, which also serve as viral vectors. Our results further indicate a shortage of complete NiV genomes, which would be instrumental in gaining a better understanding of NiV's molecular evolution and preventing future outbreaks. Our investigation also underscores the critical need to strengthen genomic surveillance based on complete NiV genomes that will aid thorough genetic characterization of the circulating NiV strains and the phylogenetic relationships between the henipaviruses. This approach will better prepare us to tackle the challenges posed by the NiV virus and other emerging viruses.

Nipah Virus: A Multidimensional Update.

Nipah virus (NiV) is an emerging zoonotic paramyxovirus to which is attributed numerous high mortality outbreaks in South and South-East Asia; Bangladesh's Nipah belt accounts for the vast majority of human outbreaks, reporting regular viral emergency events. The natural reservoir of NiV is the Pteropus bat species, which covers a wide geographical distribution extending over Asia, Oceania, and Africa. Occasionally, human outbreaks have required the presence of an intermediate amplification mammal host between bat and humans. However, in Bangladesh, the viral transmission occurs directly from bat to human mainly by ingestion of contaminated fresh date palm sap. Human infection manifests as a rapidly progressive encephalitis accounting for extremely high mortality rates. Despite that, no therapeutic agents or vaccines have been approved for human use. An updated review of the main NiV infection determinants and current potential therapeutic and preventive strategies is exposed.

Structural Studies of Henipavirus Glycoproteins.

Henipaviruses are a genus of emerging pathogens that includes the highly virulent Nipah and Hendra viruses that cause reoccurring outbreaks of disease. Henipaviruses rely on two surface glycoproteins, known as the attachment and fusion proteins, to facilitate entry into host cells. As new and divergent members of the genus have been discovered and structurally characterized, key differences and similarities have been noted. This review surveys the available structural information on Henipavirus glycoproteins, complementing this with information from related biophysical and structural studies of the broader Paramyxoviridae family of which Henipaviruses are members. The process of viral entry is a primary focus for vaccine and drug development, and this review aims to identify critical knowledge gaps in our understanding of the mechanisms that drive Henipavirus fusion.

Current progress towards prevention of Nipah and Hendra disease in humans: A scoping review of vaccine and monoclonal antibody candidates being evaluated in clinical trials.

OBJECTIVES: Nipah and Hendra are deadly zoonotic diseases with pandemic potential. To date, no human vaccine or monoclonal antibody (mAb) has been licensed to prevent disease caused by these pathogens. The aim of this scoping review was to identify and describe all Phase I, II, and III clinical trials of vaccine candidates or mAbs candidates designed to prevent Nipah and Hendra in humans and to compare the characteristics of the vaccine candidates to characteristics outlined in the Target Product Profile drafted by the World Health Organisation as part of the WHO Research & Development Blueprint for Action to Prevent Epidemics. METHODS: We searched 23 clinical trial registries, the Cochrane Central Register of Clinical Trials, and grey literature up to June 2023 to identify vaccine and mAb candidates being evaluated in registered clinical trials. Vaccine candidate and trial characteristics were double-extracted for evaluation and the vaccine candidate characteristics were compared with the preferred and critical criteria of the World Health Organisation's Target Product Profile for Nipah virus vaccine. RESULTS: Three vaccine candidates (Hendra Virus Soluble Glycoprotein Vaccine [HeV-sG-V], PHV02, and mRNA-1215) and one mAb (m102.4) had a registered human clinical trial by June 2023. All trials were phase 1, dose-ranging trials taking place in the United States of America or Australia and enrolling healthy adults. Although all vaccine candidates meet the dose regimen and route of administration criteria of the Target Product Profile, other criteria such as measures of efficacy and reactogenicity will need to be evaluated in the future as evidence becomes available. CONCLUSION: Multiple vaccine candidates and one mAb candidate have reached the stage of human clinical trials and are reviewed here. Monitoring progress during evaluation of these candidates and candidates entering clinical trials in the future can help highlight many of the challenges that remain.