I think this is the first time I've seen an explanation of the mechanics of how SARS-CoV-2 can mess you up. Or at least one way, as it may have multiple. Spike proteins are nasty monkey funsters.
#^SARS-CoV-2 Spike Protein Induces Hemagglutination: Implications for COVID-19 Morbidities and Therapeutics and for Vaccine Adverse EffectsExperimental findings for SARS-CoV-2 related to the glycan biochemistry of coronaviruses indicate that attachments from spike protein to glycoconjugates on the surfaces of red blood cells (RBCs), other blood cells and endothelial cells are key to the infectivity and morbidity of COVID-19. To provide further insight into these glycan attachments and their potential clinical relevance, the classic hemagglutination (HA) assay was applied using spike protein from the Wuhan, Alpha, Delta and Omicron B.1.1.529 lineages of SARS-CoV-2 mixed with human RBCs. The electrostatic potential of the central region of spike protein from these four lineages was studied through molecular modeling simulations. Inhibition of spike protein-induced HA was tested using the macrocyclic lactone ivermectin (IVM), which is indicated to bind strongly to SARS-CoV-2 spike protein glycan sites. The results of these experiments were, first, that spike protein from these four lineages of SARS-CoV-2 induced HA. Omicron induced HA at a significantly lower threshold concentration of spike protein than the three prior lineages and was much more electropositive on its central spike protein region. IVM blocked HA when added to RBCs prior to spike protein and reversed HA when added afterward. These results validate and extend prior findings on the role of glycan bindings of viral spike protein in COVID-19. They furthermore suggest therapeutic options using competitive glycan-binding agents such as IVM and may help elucidate rare serious adverse effects (AEs) associated with COVID-19 mRNA vaccines, which use spike protein as the generated antigen.
This hemagglutinating property of SARS-CoV-2 has important clinical consequences. First, with trillions of RBCs each circulating through narrow pulmonary capillaries about once per minute, even small, dynamically aggregating and disaggregating RBC clumps (as can form even in the absence of pathogens) can impede RBC oxygenation. Peripheral ischemia, endothelial damage and vascular occlusion are indeed frequently observed in serious cases of COVID-19, as reviewed. In COVID-19 patients, damaged endothelium of pulmonary capillaries is often observed adjoining relatively intact alveoli, while hypoxemia is manifested despite normal breathing mechanics. These morbidities of COVID-19 parallel those of severe malaria, in which clumping of parasite-infected RBCs to other RBCs via SA terminal residues and endothelial cyto-adhesion also often result in fatal outcomes.
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covid-19
