Nanoparticle-Delivered COVID-19 Vaccine Presents Advantages, Clinical Trials Show

Researchers at Cleveland Clinic's Global Center for Pathogen Research & Human Health have developed a potential new nanoparticle-delivered COVID-19 vaccine that has presented strong effectiveness in preclinical illness models.

A EurekAlert report said that findings which mBio published (Development of Spike Receptor-Binding Domain Nanoparticles as a Vaccine Candidate against SARS-CoV-2 Infection in Ferrets) showed that the vaccine yielded potent neutralizing antibodies among preclinical prototypes and prevented infection as well, and symptoms of disease amidst exposure to SARS-CoV-2, the type of coronavirus that causes COVID-19.

One more reason for the early appeal of this vaccine candidate is that it may be thermostable. Meaning, it would be simpler to transport and store compared to the presently authorized COVID-19 vaccines, as shown on the Global News YouTube video below.

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Delivering Antigens via Nanoparticles

According to director of the Global Center for Human Health & Pathogen Research, Jae Jung, PhD, also co-senior author of the study, this COVID-19 candidate is delivering antigens to stimulate an immune reaction via nanoparticles brought out from ferritin, a protein that exists in nearly all living organisms.

Such a protein, added by the co-senior author, is an appealing biomaterial for vaccine and drug delivery for several reasons, which include that it does not need strict control of temperature.

A graduate student in the lab of Dr. Jung, Dokyun Kim, also the co-first author on the study said, this would intensely ease both shipping and storage limitations, which are challenges the study authors are currently experiencing in national distribution initiatives. The graduate student added that it would be advantageous too, for distribution to developing nations.

Other benefits of this protein nanoparticles include minimization of cellular impairment and offering stronger immunity at lower doses compared to the traditional protein subunit vaccines as protection from other diseases like influenza, for one.

Ferritin Nanoparticles

The research group's vaccine uses ferritin nanoparticles to transport tiny, weakened fragments from the SARS-CoV-2 spike protein's region that selectively binds to the entry point of humans for the virus. Such a fragment is also known as RBD or receptor-binding domain.

Essentially, when the SARS-CoV-2 RBD binds with angiotensin-converting enzyme 2 or ACE2, a human protein, the virus can penetrate host cells and start replicating.

The study authors tested their COVID-19 vaccine candidate on a ferret model of the disease. Said model reflects the immune response of a human and development of disease better than other models used in preclinical research.

Dr. Jung, considered as a foremost authority when it comes to virology and virus-induced cancers, formerly developed the first COVID-19 ferret of the world, a discovery that has substantially advanced study into SARS-CoV-2 contagions and spread.

Initial Dose Administered

In this research, the study investigators administered an initial dose of their vaccine candidate, followed by two booster shots given 14 and 28 days after.

One group was given the vaccines intramuscularly while another one got them both through intramuscular and intranasal procedures.

Following the second booster, all vaccinated models yielded strong neutralizing antibodies. This proposes that repeated exposure to the RBD antigen prepared successfully the immune systems to quickly combat the virus.

Several days later, the second booster, specifically, 31 days from the initial vaccine dose, the study authors had the models exposed to high SARS-CoV-2 concentrations.

Protection from Clinical Symptoms and Lung Impairment

A similar report from Medical Xpress specified that compared to the placebo group that got adjuvant-only vaccines, those that were given the RBD-nanoparticle vaccine were more shielded from clinical symptoms and lung impairment linked to the infection.

The study results propose the vaccine candidate helped stop infection and severe disease. A combination of intramuscular and intranasal immunization presented more potent shield immunity and quicker viral clearance compared to intramuscular immunization alone.

Both were substantially more effective compared to adjuvant-only injection. More studies will be essential to unveil the mechanisms behind these deferential advantages.