Disproving autoimmune risk of mRNA shot

Question

Seeing a lot of potential misinformation about mRNA vaccines.Specifically that some of the motifs of the Covid-19 spike protein have similarity to syncytin-1, which if true might trigger an autoimmune response.Looking at Protein Database for syncytin-1 https://cutt.ly/chQ27vQand for Cov-19 spike https://cutt.ly/ehQ9tlDand running the FASTA through a sequence checker https://cutt.ly/chQ9szisimilarities are not particularity high at first glance. But I know very little about this.difflogo.com also allows you to compare motifs but I was having trouble uploading the proper file type.What is the similarity threshold for a protein to be considered a autoimmune risk?Can someone with knowledge enlighten me?

rolph · Accepted Answer

the primary sequence is important to consider, there must be a long enough stretch of sequence similarity to facilitate antibody binding.
the homologous sequence must also be exposed to the exterior solvent system, not folded away inside the 2' and 3' structure. thus folding is important.
perhaps an ELISA comparing syncytin-1 with Cov-19 S protien for binding homology of either set of antibodies, would be revealing either way.
for your conveinience :
https://en.wikipedia.org/wiki/Antibody
https://en.wikipedia.org/wiki/Immune_complex

giantg2 · Answer

Does this vaccine contain any adjunctives or other additives? Autoimmune issues are not necessarily tied to the proteins in the vaccine. Sometimes adjunctives can (are thought to) potentially trigger underlying autoimmune conditions.We probably won't know the edge case adverse effects until we have millions of diverse people vaccinated.