Crystal structure of the C-terminal domain of envelope protein VP37 from white spot syndrome virus reveals sulphate binding sites responsible for heparin binding

VP37 Protein Inhibitors for Mpox Treatment: Highlights on Recent Advances, Patent Literature, and Future Directions

Monkeypox disease (Mpox) has threatened humankind worldwide since mid-2022. The Mpox virus (MpoxV) is an example of Orthopoxviruses (OPVs), which share similar genomic structures. A few treatments and vaccines are available for Mpox. OPV-specific VP37 protein (VP37P) is a target for developing drugs against Mpox and other OPV-induced infections such as smallpox. This review spotlights the existing and prospective VP37P inhibitors (VP37PIs) for Mpox. The non-patent literature was collected from PubMed, and the patent literature was gathered from free patent databases. Very little work has been carried out on developing VP37PIs. One VP37PI (tecovirimat) has already been approved in Europe to treat Mpox, while another drug, NIOCH-14, is under clinical trial. Developing tecovirimat/NIOCH-14-based combination therapies with clinically used drugs demonstrating activity against Mpox or other OPV infections (mitoxantrone, ofloxacin, enrofloxacin, novobiocin, cidofovir, brincidofovir, idoxuridine, trifluridine, vidarabine, fialuridine, adefovir, imatinib, and rifampicin), immunity boosters (vitamin C, zinc, thymoquinone, quercetin, ginseng, etc.), and vaccines may appear a promising strategy to fight against Mpox and other OPV infections. Drug repurposing is also a good approach for identifying clinically useful VP37PIs. The dearth in the discovery process of VP37PIs makes it an interesting area for further research. The development of the tecovirimat/NIOCH-14-based hybrid molecules with certain chemotherapeutic agents looks fruitful and can be explored to obtain new VP37PI. It would be interesting and challenging to develop an ideal VP37PI concerning its specificity, safety, and efficacy.

Oral vaccination for sustainable disease prevention in aquaculture-an encapsulation approach

The prevalence of infectious diseases in the aquaculture industry and a limited number of safe and effective oral vaccines has imposed a challenge not only for fish immunity but also a threat to human health. The availability of fish oral vaccines has expanded recently, but little is known about how well they work and how they affect the immune system. The unsatisfactory efficacy of existing oral vaccinations is partly attributable to the antigen degradation in the adverse gastrointestinal environment of fishes, the highly tolerogenic gut environment, and inferior vaccine formulation. To overcome such challenges in designing: an easier, cost-efficient, and effective vaccination method, several encapsulation methods are being adopted to safeguard antigens from the intestinal atmosphere for their immunogenic functions. Oral vaccination is easily degraded by gastric acids and enzymes before reaching the immunological site; however, this issue can be solved by encapsulating antigens in poly-biodegradable nanoparticles, transgenic designed bacteria, plant systems, and live feeds. To enhance the immunological impact, each antigen delivery method operates at a different level. Utilizing nanotechnology, it has been possible to regulate vaccination parameters, target particular cells, and lower the antigen dosage with potent nanomaterials such as chitosan, poly D,L-lactic-co-glycolic acid (PLGA) as vaccine carriers. Live feeds such as Artemia salina can be utilized as bio-carrier, owing to their appropriate size and non-filter feed system, through a process called bio-encapsulation. It ensures the protection of antigens over the fish intestine and ensures complete uptake by immune cells in the hindgut for increased immune response. This review comprises recent advances in oral vaccination in aquaculture in terms of an encapsulation approach that can aid in future research.

Expression and purification of S5196-272 and S6200-317 proteins from Tilapia Lake Virus (TiLV) and their potential use as vaccines

Tilapia Lake Virus Disease (TiLVD) is caused by Tilapia Lake Virus (TiLV), and it has a cumulative mortality rate of up to 90% in Nile tilapia (Oreochromis niloticus). TiLV is a negative enveloped single-stranded RNA virus with 10 genomic segments. Segment 5 (S5) and segment 6 (S6) were predicted to include a signaling peptide, suggesting that the encoded proteins of these two segments may exist as part of the virus envelope. Based on bioinformatic predictions, the S5 and S6 proteins in this study were produced, including S5_27-343, S5_27-172, S5_196-272, S6_30-317, S6_30-190, and S6_200-317. All proteins were tested for their expression in Escherichia coli. Only S5_196-272 and S6_200-317 were expressed as soluble and insoluble proteins, respectively. The soluble protein was purified using affinity chromatography, whereas the insoluble protein was solubilized using 6 M urea lysis buffer before purification. Both proteins were further purified using gel filtration chromatography, and the results showed a symmetric peak of both proteins suggested a high degree of uniformity in the conformation of these proteins. Antigenicity results indicated that these proteins were recognized by serum from TiLV-infected fish. The immunization tests revealed that serum antibodies levels in Nile tilapia produced by S5_196-272 and S6_200-317 were significantly increased (p-value < 0.05) at 7 days post-immunization (dpi) compared to antibody levels on Day 0 (D0). All the results combined suggested a potential vaccine candidate of S5 and S6 for TiLV protection in Nile tilapia.