In this article published in Frontiers of Immunology (July 2022), “Multisystem Inflammatory Syndrome in Children and Long COVID: The SARS-CoV-2 Viral Superantigen Hypothesis,” revealed some incredibly shocking findings. In the spike protein motif, a viral super antigen complex and neurotoxin were found.
The authors propose that in the context of an intense antiviral immune response, inefficient viral clearance associated with SARS-CoV-2 (spike) persistence and repeated viral exposure may lead to uncontrolled and maladapted immune responses that cross-react with autoantigens leading to autoimmune disease.
As for the neurotoxin, the portion (Y674QTQTNSPRRAR685) of the SAg-like motif (E661-R685) homologous to alpha-neurotoxin motifs from snake venom. The identification of these neurotoxin motifs in SARS-CoV-2 raises the possibility that spike may also have direct neurotoxic activity and contribute to the neurological symptoms.