Be aware of SARS-CoV-2 spike protein: There is more than meets the eye

“The COVID-19 pandemic necessitated the rapid production of vaccines aimed at the production of neutralizing antibodies against the COVID-19 spike protein required for the corona virus binding to target cells. The best well-known vaccines have utilized either mRNA or an adenovirus vector to direct human cells to produce the spike protein against which the body produces mostly neutralizing antibodies… 

… However, recent papers have reported intriguing, but also disturbing, findings concerning detrimental actions of the spike protein.

One paper still in preprint stage at Cell reported that certain antibodies in the blood of patients infected with SARS-CoV-2 appear to change the shape of the spike protein so as to make it more likely to bind to cells and infect them. Evidently, antibodies against the RBD are protective, but antibodies against the N-terminal domain (NTD) induced the open conformation of the RBD enhancing the binding ability and infectivity. Another paper reported that the spike protein shares antigenic epitopes with human molecular chaperons resulting in autoimmunity against endothelial cells. In fact, the spike protein by itself (without being part of the corona virus) was shown to damage endothelium in an animal model via impaired mitochondrial function. A fourth paper reported that the spike protein could alter barrier function in an in-vitro model of the blood-brain barrier (BBB); in particular, the S1 protein promoted loss of barrier ability in an advanced 3D microfluidic model of the human BBB.  Finally, S1 protein was reported to actually cross the BBB and enter the brain of mice, possibly leading to neuroinflammation. In fact, another recent study reported blood vessel damage and inflammation, but no infection, in brains of patients with COVID-19.”