Adhesin binding prevention

A vaccine which prevents adhesin binding

For the development of the Covid-19 vaccine, scientists used previous knowledge and data from the vaccine development process against SARS and MERS. The starting point was understanding the way how the virus is reacting with membrane proteins. key points included research with the spike (S) protein and nucleocapsid (N) protein. Besides lab results and theory, research mostly relied on machine learning tools. The reverse vaccinology tool Vaxign was irreplaceable in the prediction of COVID-19 patient's responses. This technology helped in finding some constant data as it was with the N protein, which proved to be conserved. 

An additional point was understanding of endothelial cell adhesion molecules. Many patients had severe cases of coagulation disfunction and it proved to be caused by increased expression of endothelial cell adhesion molecules. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7337874/)

Proteomic gave us more data about the set of proteins responsible for coronavirus infectivity and six of these proteins proved to be adhesins. Here are 5 types of nonstructural proteins (nsp3, 3CL-pro, and nsp8–10)plus S protein. They are “crucial to the viral adhering and host invasion”. 

One step backward to see about adhesions activity:

“Adhesins are cell-surface components or appendages of bacteria that facilitate adhesion or adherence to other cells or to surfaces, usually in the host, they are infecting or living in. Adhesins are a type of virulence factor.”

Why is knowledge about adhesins so important in the process of developing COVID-19 vaccine? 

Being located at the surface of the membrane and accessible to antibodies, adhesins are key points for the development of vaccineÎ. Previous data show acquired immunity and model organisms were E.coli and human volunteers.

Challenging for researchers was exploring the anti-adhesin immunity concept.  

This is how bacterial adhesins work: 

“First, a large number of different bacterial adhesins target the same human tissues. Further, an individual bacterium can produce multiple different types of adhesin, at different times, in different places, and response to different environmental triggers. Finally, many adhesins present as different immunologically distinct antigenic varieties, even within the same clone (as is the case in Neisseria gonorrhoeae)."

Using bacterias as a transitional host is one of the alternatives for the virus to find the final host. That is why prevention and high hygiene is so important and, at the same time, present obstacle.

Despite these challenges, progress is being made in the creation of anti-adhesion vaccines.