biostudies-literatureMotsoeneng BMPoliomyelitis Research FoundationDepartment of Science and TechnologyCollaborative Influenza Vaccine InnovationNIAID NIH HHSCentre for the AIDS Program of ResearchDepartment of Science and InnovationUniversity of the WitwatersrandNIHCenters of Excellence for Influenza Research and ResponseSouth African National Research FoundationDepartment of Science and Innovation, South AfricaSouth AfricaNational Research FoundationNational Research Foundation, South Africa1329-1336https://www.ebi.ac.uk/biostudies/studies/S-EPMC12102481biostudies-literatureUnknown230(6)<h4>Background</h4>Future vaccine candidates aim to elicit antibodies against the conserved hemagglutinin stalk domain. Understanding the protective mechanism of these antibodies, which mediate broad neutralization and Fc-mediated functions, following seasonal vaccination is critical.<h4>Methods</h4>Plasma samples were obtained from pregnant women with or without HIV-1 enrolled in a randomised trial (138 trivalent inactivated vaccine [TIV] and 145 placebo recipients). Twenty-three influenza cases were confirmed within 6 months postpartum. We measured H1 stalk-specific antibody-dependent cellular phagocytosis (ADCP), complement deposition (ADCD) and cellular cytotoxicity (ADCC) at enrolment and 1-month postvaccination.<h4>Results</h4>Lower H1 stalk-specific ADCP and ADCD activity was detectThe Journal of infectious diseasesHemagglutinin Stalk-Specific Fc-Mediated Functions Are Associated With Protection Against Influenza Illness After Seasonal Influenza Vaccination.PMC1210248175N93021C0001475N93019C0005120/3698341Richardson SIMotsoeneng BMMoore PLDhar NKrammer FMadhi SANunes MCfalseHemagglutinin Stalk-Specific Fc-Mediated Functions Are Associated With Protection Against Influenza Illness After Seasonal Influenza Vaccination.<h4>Background</h4>Future vaccine candidates aim to elicit antibodies against the conserved hemagglutinin stalk domain. Understanding the protective mechanism of these antibodies, which mediate broad neutralization and Fc-mediated functions, following seasonal vaccination is critical.<h4>Methods</h4>Plasma samples were obtained from pregnant women with or without HIV-1 enrolled in a randomised trial (138 trivalent inactivated vaccine [TIV] and 145 placebo recipients). Twenty-three influenza cases were confirmed within 6 months postpartum. We measured H1 stalk-specific antibody-dependent cellular phagocytosis (ADCP), complement deposition (ADCD) and cellular cytotoxicity (ADCC) at enrolment and 1-month postvaccination.<h4>Results</h4>Lower H1 stalk-specific ADCP and ADCD activity was detect2024-01-01T00:00:00Z2024 Dec2026-05-29T14:23:54.971Z2026-04-08T04:59:51.698ZS-EPMC121024813874369210.1093/infdis/jiae241