biostudies-literatureKlingler JBLRD VANIAID NIH HHSNational Institutes of HealthU.S. Department of Veterans Affairs1382619https://www.ebi.ac.uk/biostudies/studies/S-EPMC11109367biostudies-literatureUnknown15<h4>Introduction</h4>Antibodies against the SARS-CoV-2 spike protein are a critical immune determinant for protection against the virus. While virus neutralization is a key function of spike-specific antibodies, antibodies also mediate Fc-dependent activities that can play a role in protection or pathogenesis.<h4>Methods</h4>This study characterized serum antibody responses elicited after two doses of heterologous adenovirus-vectored (Ad26/ Ad5) vaccines.<h4>Results</h4>Vaccine-induced antibody binding titers and Fc-mediated functions decreased over six months, while neutralization titers remained stable. Comparison of antibody isotypes elicited after Ad26/Ad5 vs. LNP-mRNA vaccination and after infection showed that anti-spike IgG1 were dominant and produced to high levels in all groups. TFrontiers in immunologyHeterologous Ad26/Ad5 adenovirus-vectored vaccines elicited SARS-CoV-2-specific antibody responses with potent Fc activities.PMC11109367IK6 BX004607HHSN272201400008C75N93019C00051R01 AI140909R21 AI148033R21 AI149033U01 AI141990U01 AI150747R01 AI123449I01 BX005794R01 AI139290AI139290, AI123449, AI1498033, 75N93019C00051, HHSN272201400008C, HHSN272201400006C, AI141990, AI150747, AI140909I01BX005794, 1IK6BX004607HHSN272201400006CEmami-Gorizi RRao PGAlvarez RAAmanat FGleason CUpadhyay CSimon VKowdle SLee BKlingler JPerandones CHioe CEBandres JCKleiner GEdelstein AfalseHeterologous Ad26/Ad5 adenovirus-vectored vaccines elicited SARS-CoV-2-specific antibody responses with potent Fc activities.<h4>Introduction</h4>Antibodies against the SARS-CoV-2 spike protein are a critical immune determinant for protection against the virus. While virus neutralization is a key function of spike-specific antibodies, antibodies also mediate Fc-dependent activities that can play a role in protection or pathogenesis.<h4>Methods</h4>This study characterized serum antibody responses elicited after two doses of heterologous adenovirus-vectored (Ad26/ Ad5) vaccines.<h4>Results</h4>Vaccine-induced antibody binding titers and Fc-mediated functions decreased over six months, while neutralization titers remained stable. Comparison of antibody isotypes elicited after Ad26/Ad5 vs. LNP-mRNA vaccination and after infection showed that anti-spike IgG1 were dominant and produced to high levels in all groups. T2024-01-01T00:00:00Z20242026-04-12T19:09:43.355Z2026-04-08T03:17:56.223ZS-EPMC111093673877967110.3389/fimmu.2024.1382619