Commonly respiratory viruses are contagious viruses that cause respiratory infections. These viruses harm the respiratory system and cause infection in the body. Here we are going to discuss the role of nano-vaccine for respiratory infection and the use of nanoparticles against respiratory viruses.
What are Respiratory Viruses?
Respiratory viruses are types of viruses that are transferred through the respiratory territory. Virus particles are mainly emitted through the respiratory tract of a diseased person or animal through sneezing, coughing, talking, or barking.
The aerosol produced by sneezing contains numerous one million droplets with a diameter of fewer than 10 µm, which evaporate quickly to produce a droplet core, which is adjourned in the air for some time. Larger droplets (maximum 100μm) contain more virions but fall to the ground within seconds. They pose a danger to anyone directly in the line of fire.
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How respiratory viruses are spread?
Respiratory infections can be spread through direct contact. For example, kissing or transferring nasal or oral fluid from the hand to the nose or mouth. At the peak of colds, these excretions are mainly abundant, and it is easy to reach tissues, towels, toothbrushes, tableware, handles, etc.
Respiratory viruses Examples:
Viruses that infect the lower respiratory tract of humans include influenza virus, respiratory syncytial virus (RSV), parainfluenza virus, and adenovirus. The outbreak of periodic influenza viruses has brought a huge disease burden to children and the elderly, causing 3 to 5 million serious illnesses and nearly 290,000 to 650,000 deaths worldwide each year (9). RSV and parainfluenza virus infections are the main causes of hospitalizations for acute respiratory infections in children, causing 45% and 40% of hospitalizations in children, respectively.
Role of nano-vaccine for respiratory infection
Use of nanoparticles against respiratory viruses:
The use of particles with relevant antigen residues, such as nanoplatforms, is of interest as an alternative to conventional vaccines. These nanomaterials can be achieved from biological sources and/or can be synthetic. Currently, there are a variety of particles tested as antigen carriers, including inorganic and polymer nanoparticles, virus-like particles (VLP), liposomes, and self-assembled protein nanoparticles.
The main advantage of these materials lies in their size (at least one size must be nano-scale) because many biological systems (such as viruses and proteins) are nano-scale. In addition, nanoparticles can be designed to allow the incorporation of various molecules including antigens, which makes them very attractive in vaccinology.
Nanoparticles and the respiratory immune system:
The respiratory mucosa is the main site of virus invasion and infection, and its replication occurs in the hair cells of the upper respiratory tract (URT). Consequently, the infection ranges to the lower respiratory tract (LRT) from virus-rich excretions and leftovers of infected URT cells. Nasal-associated lymphoid tissue (NALT) is the first inhaled antigen credit site located in URT and is an important route of defense against respiratory viruses. NALT is found in rodents, birds, and primates.
This configuration is categorized by aggregates of lymphoid cells situated in the nasopharyngeal cavity. In humans, the Waldever ring composed of adenoids and tonsils is considered equivalent to the NALT structure, which contains multiple narrow epithelial tubes. NALT includes lymphoid follicles (B cell area), inter-follicular area (T cell area), aggregates of macrophages, and dendritic cells (DC). These molecules are activated when activated Can support the elimination of infectious substances.
Polymers are composed of macromolecules composed of monomer units. Depending on the structure, the polymer can be linear, slightly branched, or hyperbranched (3D network) polymer. Polymer nanoparticles can be achieved from the polymerization of monomer units or pre-shaped polymers. These nanoparticles have fascinated consideration in the medical field due to their bendable properties (size, composition, and surface properties), which allow controlled release, the ability to combine therapy and imaging (radiology), and the safety of drug molecules.
Self-assembled protein nanoparticles and VLP
Self-assembled protein nanoparticles (SAPN) are structures obtained by oligomerization of monomeric proteins. The protein components are mainly obtained through recombinant technology and are considered safe for biomedical applications. The diameter of SAPN can be designed to be 20-100nm. It is similar to the size of many viruses. Therefore, it is considered to be a candidate for nano-vaccine against viruses through respiratory viruses.
For example, the nucleoprotein (N) extracted from the viral nucleocapsid. And this is used to select SANP designed to elicit an immune response against RSV. N protein is the main target of antigen-specific cytotoxic T lymphocyte response. The self-assembly of the N protein promoter leads to the formation of supramolecular nanorings with a diameter of 15 nm.
There are many inorganic nanoparticles suitable for biomedical applications. These include superparamagnetic nanoparticles (iron oxide nanoparticles), quantum dots, and plasmon nanoparticles (gold and silver nanoparticles). Inorganic materials are mainly used as tools with better therapeutic, biodistribution, and pharmacokinetic efficacy. However, in essence, a single inorganic core nanoparticle will not be suitable for biological fluids due to particle aggregation.
Therefore, in the medical field, these nanoparticles are often covered by organic molecules through adsorption or chemical reactions. In fact, these biocompatible nanoparticles can be defined as complex hybrid resources. They also have an inorganic core and an organic external coating. Between inorganic nanoparticles, gold nanoparticles (AuNP) are broadly used for vaccination. So the role of nano-vaccine for respiratory infection is worth considering.
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