Humoral immune responses induced by Ad26.RSV.preF alone and the Ad26.RSV.preF/RSV preF protein combination vaccine
Initially, we compared antibody and Fc-effector immune responses induced by Ad26.RSV.preF alone and the Ad26.RSV.preF/RSV preF protein combination vaccine among participants in the regimen selection cohort of the phase 1/2a clinical study to determine whether the addition of RSV preF protein improved the immune responses induced by Ad26.RSV.preF in humans, as observed in previous preclinical studies (Pre-existing RSV preF-specific IgG1 and IgA1 antibodies were detected at baseline, with no substantial differences between vaccination groups (RSV preF-specific humoral immune responses induced by Ad26.RSV.preF and the Ad26.RSV.preF/RSV preF protein combination vaccine. (a) IgG1, (b) IgA1, and (c) IgM GMFIs were measured in serum samples collected on days 1 (pre-vaccination), 15, 29, and 183 from participants receiving Ad26.RSV.preF alone (