Figure 3.

Caspase 3/7 activity for the determination of the antiviral activity of anti-SARS-CoV-2 agents and neutralization assays

(A) Dose-response curves and concentrations that inhibit virus infection by 50% (IC50) of antiviral agents as determined by caspase 3/7 activity and immunostaining for the coronavirus S protein in G614 (MOI 0.01)-infected Caco-2-F03 cells 24 h postinfection.

(B) Effects of the approved anti-SARS-CoV-2 drug remdesivir on cellular levels of the viral NP protein in G614 (MOI 1)-infected air liquid interface (ALI) cultures of primary human bronchial epithelial (HBE) cells 120 h postinfection.

(C) Effects of remdesivir on caspase 3/7 activity and virus titers (genomic RNA copy numbers determined by PCR) in G614 (MOI 1)-infected ALI HBE cultures 120 h postinfection.

(D) Effects of remdesivir on caspase 3/7 activity and virus titers in G614 (MOI 1)-infected primary human cardiomyocytes (CMS) 48 h postinfection.

(E) Correlation of the neutralization capacity of sera derived from seven donors two weeks after their second dose of the mRNA-1273 vaccine determined by caspase 3/7 activity or cytopathogenic effect (CPE) scoring in D614-, Alpha-, and Delta-infected Caco-2-F03 cells 48 h postinfection. Correlations were determined using the Pearson correlation coefficient.

(F) Determination of neutralization titers by caspase 3/7 activity or CPE scoring using sera derived from seven donors two weeks after their second dose of the mRNA-1273 vaccine in Caco-2-F03 cells infected with D614, Alpha, and Delta isolates 72 h postinfection. p values were calculated using paired t-test. P-values were determined by ANOVA.

Results are expressed as the mean ± standard deviation.