Once developed, it could be the ideal vaccine for the annual Covid booster that will most likely begin after the summer. Because the serum target is the “N” protein, a protein which, unlike the more well-known spike involved in the development of current vaccines, shows almost no mutation between the variants known so far. Not only that: the involvement of the N protein seems to generate an immune memory in the lungs that could guarantee a lasting protective effect over time. Here is the good news of a study developed by researchers fromHigher Institute of Health on mice showing very promising results.
Current vaccines developed on the Wuhan strain
One of the most debated issues currently is the protection of current vaccines against variants and in particular against the latest, the highly contagious Omicron. If the protection from severe forms, especially after the booster dose, is very high (above 90% against hospitalizations), this is not the case for infections. In fact, the current vaccines do not seem to guarantee an effective shield against infections also because the current sera were developed on the original strain of the virus, that of Wuhan. Now in view of the fourth dose or rather the first annual booster to be done in the autumn, we are thinking about the production of a new vaccine developed on the Omicron variant: in this sense Pfizer has already announced that by March it could already leave its laboratories. But as the ECDC (European center for disease prevention and control) also recalled, “Omicron is not necessarily the last variant we see”
The target is the N protein that changes less than the Spike
The study just published in the journal Viruses and conducted by researchers from the National Center for Global Health of the National Institute of Health has shown that this new innovative approach generates an effective and lasting immune response in mice infected with Sars-cov-2. The method, as mentioned, is based on a new strategy that has selected the N protein as a target, unlike the more well-known spike at the center of the current vaccines, it shows almost no mutation between the variants known so far. The new mechanism is based on the engineering of nanovesicles naturally released by muscle cells and could overcome the limitations of current vaccines on antibody decay and loss of efficacy against emerging variants.
Immune memory in the respiratory tract
The ISS team of researchers has shown that, when the extracellular vesicles are loaded with the N protein of the Sars-cov-2 nucleocapsid, an immune reaction can be generated in mice such as to induce substantial protection from infection with very high viral loads. . Furthermore, in the animal model studied, the developed technique is able to generate an immune memory in the respiratory tract, an essential condition for a lasting effect of any vaccination strategy against respiratory pathogens. “All cells constantly release tiny lipid-based vesicles defined extracellular vesicles – explains Maurizio Federico, head of the Center and senior author of the study – and the technique developed in Iss is able to load these natural nanovesicles with sars-cov proteins. 2. These engineered nanovesicles are processed by the immune system in order to generate strong cellular immunity orchestrated by a family of lymphocytes identified as cd8 lymphocytes ».
Now studies on safety and tolerability
The Istituto Superiore di Sanità now has additional studies in the pipeline to establish parameters such as the safety of the vaccine platform and its tolerability. These parameters will be essential to lay the foundations for future clinical studies aimed at definitively confirming the efficacy of this discovery. It will also be necessary to understand whether any vaccines developed with the new platform should be integrated with forms of immunization based on technologies currently in use, for example based on mRNA. The study, funded through intramural funding from the ISS, demonstrates the Institute’s commitment and its researchers in the search for strategies that could lead to more effective Covid vaccines.