Recombinant protein subunit new crown vaccine is safe and effective in three animal trials
There are new developments in the new crown vaccine! A study published in Science Translational Medicine (Science Sub-Journal) reported that a new type of new coronavirus recombinant protein subunit vaccine can stimulate antibody responses in three animal models (mouse, hamster, and macaque), and can prevent the new coronavirus Transmission and infection to unvaccinated hamsters. The authors of this study said that this new design is very promising as one of the options for the new crown vaccine in the future.
The existing new crown vaccine has saved tens of millions of lives, but the new vaccine will give clinicians and medical institutions more drug choices. Most of the existing new coronavirus vaccines use mRNA or modified viral vectors to stimulate the immune system; a small number of vaccines use small molecules and harmless viral protein subunits to evoke an immune response.
Protein subunit vaccines are known for their safety and require multiple injections, but this type of new crown vaccine rarely enters the clinical trial stage. In this study, Yangtao Wu and colleagues analyzed the protein from SARS-CoV-2 and found that the viral spike outer domain protein (hereinafter referred to as StriFK) can induce neutralizing antibodies in mice with high intensity. Later, on the basis of StriFK, the team added a zinc-aluminum mixed adjuvant that can further enhance the immune response to make a new protein subunit vaccine.
This new formulation is safe and can induce neutralizing antibody production and T cell responses in mice, hamsters and macaques. It is worth noting that hamsters vaccinated will not infect SARS-CoV-2 to other hamsters in the same breeding space that have not been vaccinated. This means that the vaccine can prevent infection and transmission at the same time. "This vaccine alternative will enter the subclinical stage, and it is hopeful that it will be mass-produced later." The author of the article Wu concluded.
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After reading the news about the new vaccine, readers who are interested in the mechanism, advantages and disadvantages behind this vaccine, can continue reading. (The following is compiled: Phylicia)
When the new coronavirus invades cells, it mainly relies on the spike protein on the surface of the virus to interact with the receptor on the host cell membrane. This receptor is called angiotensin converting enzyme 2 (ACE2). The spike protein of the new coronavirus has two functional subunits. The S1 subunit contains the receptor binding domain, and the S2 subunit mediates the fusion of the virus and the host cell membrane. Therefore, there is a lot of evidence that antibodies that bind to spike protein will be used in the prevention and treatment of new crowns (the spike protein and antibody are combined, and the probability of binding to ACE2 of the host cell is reduced. Antibodies are like the difference between spike protein and ACE2. The "small three") plays an important role. At present, scientists mainly use recombinant DNA technology to produce subunit vaccines to induce the body to produce neutralizing antibodies. The advantage is that it is safe and the effects of multiple injections can promote each other.
There are currently two challenges facing the study of new crown subunit vaccines. One is to ensure that the subunit vaccine can stimulate effective new crown neutralizing antibodies instead of stimulating other non-neutralizing antibodies, because other non-neutralizing antibodies can mediate viral infections. Second, compared with a complete virus vaccine or a viral vaccine, the subunit vaccine produces a weaker immune response. Therefore, it is also very important to choose appropriate adjuvants to enhance the immune response.
In this study, the study used Chinese hamster ovary cells to express various spike protein derivatives, from which StriFK was screened, and a zinc-aluminum adjuvant FH002C was added to make a vaccine called StriFK-FH002C. Compared with the concentration of neutralizing antibodies in the plasma of patients infected with COVID-19, the vaccine can induce 30 times more neutralizing antibodies after two doses, and 50-250 times more neutralizing antibodies can be produced after three doses.
At the same time, the vaccine has no systemic side effects in animal models and has good safety. The added adjuvant FH002C is of non-natural origin (unlike squalene or QS-21), and the preparation of vaccines with CHO cells is also very efficient, which is convenient for industrial large-scale production. However, it is still necessary to do a good job in the toxicology study of StriFK-FH002C before clinical trials.
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