Fig. 3

Sensitivity and dynamic ranges of anti-S1-RBD antibodies detection in DSS. DSS samples collected from 4 vaccinated individuals were tested. Paper discs, 1.2 mm in diameter (corresponding to approximately 0.25 µl fresh saliva liquid), were cut from a DSS and either added directly into the incubation solution (undiluted) or using 1 µl of s serial dilution, of up to 10,000-fold (corresponding to 1/4, 1/40, 1/400, 1/4000, 1/40,000 µl liquid saliva). Lines in four different colors represent values for four different individuals. ΔCt values were calculated using the Ct of dilution buffer minus that of Ct of sample at different concentration. The dynamic range spanned more than 3 logs and results of all investigated concentrations were within the linear range.