Fig. 6: RBD–ACE2 interaction inhibiting antibodies in sera from vaccinated volunteers.
From: Interim safety and immunogenicity results from an NDV-based COVID-19 vaccine phase I trial in Mexico
Antibodies binding to the receptor binding domain (RBD) that inhibited its interaction with the angiotensin-converting enzyme 2 (ACE2) were assessed in vaccinees’ sera using an RBD–ACE2 interaction inhibition assay at baseline and 14, 21, 28, and 42 days after the first vaccine dose administration. Individuals receiving the IM-IM regimen (left column), IN-IN regimen (middle column), or IN-IM (right column) with a high dose (top row), medium dose (middle row), or low dose (bottom row) of the vaccine are shown. Human convalescent serum (HCS) samples were added as additional controls. The cutoff established for positivity (30%) in this assay is indicated by the horizontal dotted line. The cutoff was determined by the manufacturer, and that was validated with negative control and convalescent sera by INER. Bars show the geometric mean, and the error shows the 95% confidence intervals. Statistical significance is indicated as follows: *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, Friedman’s ANOVA followed by Dunn’s multiple comparison test.
