Poliovirus Vaccination Induces a Humoral Immune Response That Cross Reacts With SARS-CoV-2

Figures

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  Figure 1. An observational study design testing the hypothesis that immunity against SARS-CoV-2 is dependent upon one's age and that poliovirus vaccination plays a vital role in this apparent protection.

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  Figure 2. Median age correlates with SARS-CoV-2 prevalence and death rate. Data were collected for the 100 countries with the highest prevalence of SARS-CoV-2 (accessed February 10, 2021). Statistically significant correlations were observed between median age and (A) prevalence of SARS-CoV-2 (Pearson r = 0.546, p < 0.001) and (B) COVID-19-related death rate (Pearson r = 0.545, p < 0.001).

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  Figure 3. Poliovirus RdRp contains one or more epitopes recognized by SARS-CoV-2 RdRp antibodies. (A) SDS-PAGE image of Poliovirus RdRp proteins from bacterial cells (Lane 1) and full SARS-CoV-2 RdRp (Lane 2). The poliovirus RdRp from bacterial cells seems to be degraded or not post-translationally modified. Both viral forms of the RdRp in their native configuration have been reported to have a molecular weight around 130 kD. (B) Western blot identification of the antigenic activity of RdRp proteins. The primary antibody was a mouse monoclonal antibody to SARS-CoV-2 RdRp protein, and the secondary antibody was a goat anti-mouse IgG/A/M HRP. Lane 1, a vaccine sample shows a line at about 35 kD; Lane 2, poliovirus RdRp expressed in bacterial cells shows a molecular weight around 50–55 kD, representing an un-modified and possibly truncated form of the RdRp; Lane 3, SARS-CoV-2 RdRp, shows a line around 130 kD.

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  Figure 4. Poliovirus vaccination shows significant increase in RdRp reactivity. (A) Comparison of sera (N = 204) before and after poliovirus immunization showed that adults gained significantly more antibodies following the poliovirus vaccination (Two-tailed t-test, ***p < 0.001). (B) Comparison of pediatric and immunized adult sera showed no significant differences between the two groups (Two-tailed t-test, p = 0.85), with immunized adults displaying similar antibody responses as immunized children.

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  Figure 5. Sera from immunized individuals demonstrate higher inhibition of SARS-CoV-2-induced CPE. Sera from five test subjects of varying ages and IPV-immunization stages were added before viral adsorption. Values show the inhibition of the SARS-CoV-2-induced CPE, as a surrogate marker for the inhibition of viral replication; inhibition percentage was calculated by average O.D. 540 nm from each well, normalized with mock and vehicle control from the same plate (see Methods).

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  Figure 6. RdRp Enzymatic Activity is blocked by polio-immune serum. RdRp polymerase activity was evaluated by fluorescence staining of de novo synthesized RNA. In the presence of diluted serum (1:1800), RdRp's activity is inhibited. Each bar represents one serum sample (17 randomly-selected samples compared to a control).