New York, Jan 9: Researchers have developed a nanoparticle vaccine that elicits a virus-neutralising antibody response after a single dose.

The team, including Peter Kim from Stanford University in the US, said that the primary target for Covid-19 vaccines is the spike protein, which is necessary for SARS-CoV-2's entry into cells.

Both of the vaccines are mRNA vaccines that cause human cells to temporarily produce the spike protein, triggering an immune response and antibody production. COVID-19 Vaccination in India: Volunteer Who Took Covaxin Trial Shot Shares Experience, Says 'No Fever or Any Other Discomfort After 9 Days'.

For the study, published in the ACS Central Science journal, the team wanted to try a different approach: a vaccine consisting of multiple copies of the spike protein displayed on ferritin nanoparticles, in a mice-based experiment.

Ferritin is an iron storage protein found in many organisms that self-assembles into a larger nanoparticle. Other proteins, such as viral antigens, can be fused to ferritin so that each nanoparticle displays several copies of the protein, which might cause a stronger immune response than a single copy.

The researchers spliced spike protein and ferritin DNA together and then expressed the hybrid protein in cultured mammalian cells. The ferritin self-assembled into nanoparticles, each bearing eight copies of the spike protein trimer. The team purified the spike/ferritin particles and injected them into mice.

After a single immunisation, mice produced neutralising antibody titers that were at least two times higher than those in convalescent plasma from Covid-19 patients, and significantly higher than those in mice immunized with the spike protein alone.

A second immunisation 21 days later produced even higher antibody levels.

Although these results must be confirmed in human clinical trials, they suggest that the spike/ferritin nanoparticles may be a viable strategy for single-dose vaccination against Covid-19, the researchers said.

(The above story first appeared on LatestLY on Jan 09, 2021 02:12 PM IST. For more news and updates on politics, world, sports, entertainment and lifestyle, log on to our website latestly.com).