Reactogenicity and safety assessment of an attenuated nanovaccine against scorpion envenomation: Preclinical study

Enhancing neutralizing antibodies against receptor binding domain of SARS-CoV-2 by a safe natural adjuvant system

The receptor binding domain (RBD) plays a pivotal role in the viral entry as it enables the engagement of severe acute respiratory syndrome 2 (SARS-CoV-2) with the human angiotensin-converting enzyme 2 (ACE2) receptor for host cell entry. RBD is the major target for developing viral inhibitors and vaccines. Expression of recombinant RBD in E.coli is highly scalable with a low-cost procedure despite its high expression level compared to expression in mammalian and yeast cells. Using an alternative natural adjuvant system instead of alum adjuvant, increased immunogenicity of RBD antigen in serological assay including direct ELISA and surrogate Virus Neutralization Test (sVNT) was demonstrated with high levels of IgGs and neutralizing antibodies in mice sera immunized with RBD:AlSa (Alum and Sodium alginate) formulation. The sVNT is a simple and fast test that can be used instead of the conventional virus neutralization test requiring live virus and BSL3 laboratory to detect total neutralizing antibodies against RBD. Additionally, results showed a safety profile for sodium alginate which supported using it as an alternative natural adjuvant.

Nanobiotechnology with Therapeutically Relevant Macromolecules from Animal Venoms: Venoms, Toxins, and Antimicrobial Peptides

Some diseases of uncontrolled proliferation such as cancer, as well as infectious diseases, are the main cause of death in the world, and their causative agents have rapidly developed resistance to the various existing treatments, making them even more dangerous. Thereby, the discovery of new therapeutic agents is a challenge promoted by the World Health Organization (WHO). Biomacromolecules, isolated or synthesized from a natural template, have therapeutic properties which have not yet been fully studied, and represent an unexplored potential in the search for new drugs. These substances, starting from conglomerates of proteins and other substances such as animal venoms, or from minor substances such as bioactive peptides, help fight diseases or counteract harmful effects. The high effectiveness of these biomacromolecules makes them promising substances for obtaining new drugs; however, their low bioavailability or stability in biological systems is a challenge to be overcome in the coming years with the help of nanotechnology. The objective of this review article is to describe the relationship between the structure and function of biomacromolecules of animal origin that have applications already described using nanotechnology and targeted delivery.

Enhanced Antitumor Immune Responses via a Self-Assembled Carrier-Free Nanovaccine

Nanovaccines have emerged as promising agents for cancer immunotherapy. However, insufficient antitumor immunity caused by inefficient antigen/adjuvant loading and complicated preparation processes are the major obstacles that limit their clinical application. Herein, two adjuvants, monophosphatidyl A (MPLA) and CpG ODN, with antigens were designed into a nanovaccine to overcome the above obstacles. This nanovaccine was constructed with adjuvants (without additional materials) through facile self-assembly, which not only ensured a high loading efficacy and desirable safety but also facilitated clinical translation for convenient fabrication. More importantly, the selected adjuvants could achieve a notable immune response through synergistic activation of Toll-like receptor 4 (TLR4) and TLR9 signaling pathways, and the resulting nanovaccine remarkably inhibited the tumor growth and prolonged the survival of tumor-implanted mice. This nanovaccine system provides an effective strategy to construct vaccines for cancer immunotherapy.

How to overcome the side effects of tumor immunotherapy

The incidence of cancer is increasing year by year. Cancer has become one of the health threats of modern people. Simply relying on the surgery, chemotherapy or radiotherapy, not only the survival rate is not high, but also the quality of life of patients is not much better. Fortunately, the emergence and rapid development of cancer immunotherapy have brought more and more exciting results. However, when scientists think it is possible to overcome cancer, they find that not all cancer patients can benefit from immunotherapy, that is to say, the overall efficiency of immunotherapy is not high. Drug resistance and side effects of immunotherapy cannot be ignored. In order to overcome these difficulties, scientists continue to improve the strategy of immunotherapy and find that combination therapy can effectively reduce the incidence of drug resistance. They also found that by reprogramming tumor blood vessels, activating ferroptosis, utilizing thioredoxin, FATP2 and other substances, the therapeutic effect can be improved and side effects can be alleviated. This article reviews the principles of immunotherapy, new strategies to overcome drug resistance of cancer immunotherapy, and how to improve the efficacy of immunotherapy and reduce side effects.

Chitosan nanoparticles as a delivery platform for neurotoxin II from Androctonus australis hector scorpion venom: Assessment of toxicity and immunogenicity

In recent years, biodegradable polymers based nanoparticles received high interest for the development of vaccine delivery vehicles. In this study, chitosan nanoparticles encapsulating Aah II toxin (AahII-CNPs) isolated from Androctonus australis hector venom, were investigated as vaccine delivery system. Particles obtained by ionotropic gelation were characterized for their size, surface charge, morphology and toxin release profile from Aah II-CNPs. Toxin-nanoparticles interactions were assessed by Fourier Transform Infrared Spectrometry and X-Ray Diffraction. An immunization protocol was designed in mice to investigate anti-toxin immunity and the protective status induced by different Aah II immune formulations. Unloaded chitosan nanoparticles presenting a spherical shape and smooth surface, were characterized by a size of 185 nm, a dispersion index (PDI) of 0.257 and a zeta potential of +34.6 mV. Aah II toxin was successfully entrapped into chitosan nanoparticles as revealed by FTIR and XRD data. Entrapment efficiency (EE) and Loading capacity (LC) were respectively of 96.66 and 33.5%. Aah II-CNPs had a diameter of 208 nm, a PDI of 0.23 and a zeta potential of +30 mV. Encapsulation of Aah II reduced its toxicity and protected mice until 10 LD₅₀. Mice were immunized via a dual prime-boost scheme. Nanoentrapped Aah II immunogen elicited systemic innate and humoral immune responses as well as local spleen parenchyma hyperplasic alterations. Aah II-CNPs immunized mice withstood high lethal doses of native Aah II, one-month post-boost inoculation. This study provided encouraging and promising results for the development of preventive therapies against scorpion envenoming mainly for the populations at-risk.

Serotherapy against Voltage-Gated Sodium Channel-Targeting αToxins from Androctonus Scorpion Venom

Because of their venom lethality towards mammals, scorpions of the Androctonus genus are considered a critical threat to human health in North Africa. Several decades of exploration have led to a comprehensive inventory of their venom components at chemical, pharmacological, and immunological levels. Typically, these venoms contain selective and high affinity ligands for the voltage-gated sodium (Na_v) and potassium (K_v) channels that dictate cellular excitability. In the well-studied Androctonus australis and Androctonus mauretanicus venoms, almost all the lethality in mammals is due to the so-called α-toxins. These peptides commonly delay the fast inactivation process of Na_v channels, which leads to increased sodium entry and a subsequent cell membrane depolarization. Markedly, their neutralization by specific antisera has been shown to completely inhibit the venom’s lethal activity, because they are not only the most abundant venom peptide but also the most fatal. However, the structural and antigenic polymorphisms in the α-toxin family pose challenges to the design of efficient serotherapies. In this review, we discuss past and present accomplishments to improve serotherapy against Androctonus scorpion stings.