Molecular mimicry between SARS-CoV-2 spike glycoprotein and mammalian proteomes: implications for the vaccine.
Immunol Res. 2020 10 ;68(5):310-313. Epub 2020 Sep 18. PMID: 32946016
The ethiopathology of the diseasome induced by the SARS-CoV-2 infection in the human host  is under intensive investigation. A likely mechanism is that the multitude of the diseases encompassed within COVID-19 derives from molecular mimicry phenomena between the virus and human proteins . The rationale is that, following an infection, the immune responses raised against the pathogen can cross-react with human proteins that share peptide sequences (or structures) with the pathogen, in this way, leading to harmful autoimmune pathologies [3, 4]. Accordingly, lungs and airways dysfunctions associated with SARS-CoV-2 infection might be explained by the sharing of peptides between SARS-CoV-2 spike glycoprotein and alveolar lung surfactant proteins . In support of this thesis, additional reports [5–8] highlight molecular mimicry and cross-reactivity as capable of explaining the SARS-CoV diseases. Of special interest, cross-reactive T cell recognition between circulating “common cold” coronaviruses and SARS-CoV-2 has been also suggested . In this scientific framework, this study comparatively analyzed the peptide sharing between SARS-CoV-2 and mammalian species. Our reasoning is that if it were true that molecular mimicry between SARS-CoV-2 and human proteins contributes to or causes COVID-19, then different levels/patterns of molecular mimicry vs. the virus should characterize the various animal species. Indeed, scarce data exist to indicate that domestic animals, for instances dogs and cats, can either transmit the virus or develop the virus-associated diseasome . In general, currently, the consensus remains that there is no evidence that infected pets are a source of SARS-CoV-2 infection for people or other pets [11, 12]. Based on this rationale and using hexa- and heptapeptides as sequence probes [13–15], the peptide overlap between SARS-CoV-2 spike glycoprotein and mammalian proteomes was analyzed.