PLS-R analysis of humoral and Fc-effector responses. PLS-R analysis was used to profile humoral and Fc-effector responses for participants receiving Ad26.RSV.preF alone (n = 8), RSV preF protein alone (n = 8), or the Ad26.RSV.preF/RSV preF protein combination vaccine (n = 15). Ad26, adenovector type 26; ADCD, antibody-dependent complement deposition; ADCP, antibody-dependent cellular phagocytosis; ADNP, antibody-dependent neutrophil phagocytosis; FcαR, Fcα receptor; FcγR, Fcγ receptor; IFN-γ, interferon-γ; Ig, immunoglobulin; LV, latent variable; MIP, macrophage inflammatory protein; PLS-R, partial least squares regression; preF, pre-fusion conformation-stabilized RSV F protein; RSV, respiratory syncytial virus.