The N and C-terminal deleted variant of the dengue virus NS1 protein is a potential candidate for dengue vaccine development.

NS1 is an elusive dengue protein, involved in viral replication, assembly, pathogenesis, and immune evasion. Its levels in blood plasm are positively related to disease severity like thrombocytopenia, hemorrhage, and vascular leakage. Despite its pathogenic roles, NS1 is being used in various vaccine formulations due to its sequence conservancy, ability to produce protective antibodies and low risk for inducing antibody-dependent enhancement. In this study, we have used bioinformatics tools and reported literature to develop an NS1 variant (dNS1). Molecular docking studies were performed to evaluate the receptor-binding ability of the NS1 and dNS1 with TLR4. NS1 and dNS1 (153 to 312 amino acid region) genes were cloned, expressed and protein was purified followed by refolding. Docking studies showed the binding of NS1 and dNS1 with the TLR4 receptor which suggests that N and C-terminal sequences of NS1 are not critical for receptor binding. Antibodies against NS1 and dNS1 were raised in rabbits and binding affinity of anti-dNS1 anti-NS1 sera was evaluated against both NS1 and dNS1. Similar results were observed through western blotting which highlight that N and C-terminal deletion of NS1 does not compromise the immunogenic potential of dNS1 hence, supports its use in future vaccine formulations as a substitute for NS1.

A novel strategy for developing a tetravalent vaccine (dvac) against dengue utilizing conserved regions from all DENV proteins.

Dengue fever is a global health issue which is infecting millions of people each year and number of reported infections are constantly increasing. Though the only commercialized vaccine i.e. dengvaxia has banned in several countries due to its potential health risk, overall vaccine holds promising potential against viruses. In this study, we have developed a novel formulation of multi-epitope peptide vaccine (dvac), which utilizes peptides from each dengue protein with >80% sequence conservancy within each serotype and their respective genotypes. Simultaneous utilization of all dengue proteins and their conservancy among dengue virus genome is targeted to evoke balanced immunity against dengue serotypes without eliciting antibody-dependent enhancement and antigenic sin like response, which are primarily responsible for severe dengue fever. Immunoinformatic approaches are used to identify the potential of dvac in inducing cytotoxic T-lymphocytes, helper T-lymphocytes, Interleukin-4, Interferon-gamma and B-cell immune responses without inducing allergic responses. Cross-reactivity of dvac with human cellular machinery is also taken into consideration to avoid any cross-reactive pathogenicity. Furthermore, interaction of dvac with immune receptors i.e. toll-like receptors (TLR3 and TLR4) using molecular docking studies revealed favorable interaction between synthetic peptide and immune receptors. Our findings suggest that designed multi-epitope peptide holds great potential to evoke balanced immunity against all dengue serotypes without eliciting any significant harmful side-effects.

Dengue proteins with their role in pathogenesis, and strategies for developing an effective anti-dengue treatment: A review.

Dengue virus is an arbovirus belonging to class Flaviviridae Its clinical manifestation ranges from asymptomatic to extreme conditions (dengue hemorrhagic fever/dengue shock syndrome). A lot of research has been done on this ailment, yet there is no effective treatment available for the disease. This review provides the systematic understanding of all dengue proteins, role of its structural proteins (C-protein, E-protein, prM) in virus entry, assembly, and secretion in host cell, and nonstructural proteins (NS1, NS2a, NS2b, NS3, NS4a, NS4b, and NS5) in viral assembly, replication, and immune evasion during dengue progression and pathogenesis. Furthermore, the review has highlighted the controversies related to the only commercially available dengue vaccine, that is, Dengvaxia, and the risk associated with it. Lastly, it provides an insight regarding various approaches for developing an effective anti-dengue treatment.