Fig 1: Influenza and HHV-6 peptides are identical to peptides in the RBD of the spike protein of SARS-CoV-2 and are recognized by antibodies in SARS-CoV-2-negative individuals(A) Localization of the influenza A H1N1 NGVEGF peptide in the spike protein of SARS-CoV-2.(B) NGVEGF is present in the critical domain of SARS-CoV-2 that interacts with the ACE2 receptor.(C) NGVKGF is situated in an immunodominant region of the neuraminidase enzyme of influenza A H1N1.(D) Localization of the HHV-6 peptide PFERDIS in the SARS-CoV-2 RBD.(E and F) Fifty-three of 328 subjects had IgG antibodies (mean MFI >6 SD) against soluble pre-fusion stabilized trimeric spike glycoprotein (SPIKE-f (HEK)).(G and H) NGVEGF-specific IgG antibody levels in COVID-19-positive and COVID-19-negative subjects, measured by ELISA.(I and J) LKPFERDIS-specific IgG antibody levels in COVID-19-positive and COVID-19-negative subjects, measured by ELISA.(K and L) NGVEGF- and LKPFERDIS-specific IgG antibody levels in serum samples from healthy donors in 2011, as measured by ELISA and prevalence of peptide-specific IgG antibody values (cutoff values are shown for OD ≥ 0.2 and >0.3) in healthy donors in 2011. (H and J) Prevalence of peptide-specific IgG antibody values (cutoff values are shown for OD > 0.2 and >0.3) in COVID-19-positive and COVID-19-negative subjects. (G and I) Unpaired t test was used to analyze the levels of IgG antibodies toward the same peptides in two different cohorts and (K) ratio paired t test was used to analyze the differences between the pairs for the levels of IgG antibodies toward different peptides in the same cohort. OD: Optical Density.
Fig 2: SARS-CoV-2-specific immunity increase in some individuals after flu vaccination(A) Flu vaccination increased inhibition of binding of spike to the ACE2 receptor as assessed with a surrogate virus neutralization assay in 14 responding individuals.(B) NGVEGF-specific IgG antibodies before and after flu and COVID vaccination in 7 healthy individuals and (C) in 12 elderly individuals living in an elderly home.(D) LKPFERDIS-specific IgG antibodies before and after flu and COVID vaccination in 7 healthy individuals and (E) in 12 individuals living in an elderly home.(F) Levels of IFN-γ producing CD4- and CD8-specific T cells stimulated with NGVEGF peptide before and after flu vaccination. Non parametric paired t test was used to analyze the same cohorts before and after vaccinations. Data are represented as mean ± SEM.
Supplier Page from Sino Biological, Inc. for Human ACE2 / Angiotensin-Converting Enzyme 2 Protein (Fc Tag), Biotinylated