Figure 4.

Ratio between O.D. values of plasma samples not adsorbed and adsorbed to recombinants RBDs of seasonal coronavirus. To assess cross-reactivity between proteins seasonal coronavirus RBDs were performed in competition ELISA assays, using 100 plasma samples from PCR+ (red) and PCR- (blue) individuals to COVID-19. The charts show the data normalized from non-adsorbed and adsorbed plasma samples against RBDs proteins from HCOV-229E (A), HCOV-NL63 (B), HCOV-OC43 (C) and HCOV-HKU1 (D). The individual plasma was used in a title of 1:500 and the recombinant RBD for the coating was diluted in 2 µg/mL (100 ng/well) and for adsorption at 20 µg/mL. The assay reading was performed at a wavelength of 492 nm and each symbol shows the value of the ratio between the O.D. values without adsorption/with adsorption. The horizontal black lines represent the mean ± SD. One-way ANOVA for repetitive measures. *p<0.01; ns, not significant.