Abstract

To evaluate immune responses to COVID-19 vaccines in adults aged 50 years and older, spike protein (S)-specific antibody concentration, avidity, and function (via angiotensin-converting enzyme 2 (ACE2) inhibition surrogate neutralization and antibody dependent cellular phagocytosis (ADCP)), as well as S-specific T cells were quantified via activation induced marker (AIM) assay in response to two-dose series. Eighty-four adults were vaccinated with either: mRNA/mRNA (mRNA-1273 and/or BNT162b2); ChAdOx1-S/mRNA; or ChAdOx1-S/ChAdOx1-S. Anti-S IgG concentrations, ADCP scores and ACE2 inhibiting antibody concentrations were highest at one-month post-second dose and declined by four-months post-second dose for all groups. mRNA/mRNA and ChAdOx1-S/mRNA schedules had significantly higher antibody responses than ChAdOx1-S/ChAdOx1-S. CD8+ T-cell responses one-month post-second dose were associated with increased ACE2 surrogate neutralization. Antibody avidity (total relative avidity index) did not change between one-month and four-months post-second dose and did not significantly differ between groups by four-months post-second dose. In determining COVID-19 correlates of protection, a measure that considers both antibody concentration and avidity should be considered.

Details

Title
Adaptive immune responses to two-dose COVID-19 vaccine series in healthy Canadian adults ≥ 50 years: a prospective, observational cohort study
Author
Gaultier, Gabrielle N. 1 ; McMillan, Brynn 2 ; Poloni, Chad 3 ; Lo, Mandy 1 ; Cai, Bing 1 ; Zheng, Jean J. 4 ; Baer, Hannah M. 5 ; Shulha, Hennady P. 1 ; Simmons, Karen 1 ; Márquez, Ana Citlali 6 ; Bartlett, Sofia R. 7 ; Cook, Laura 8 ; Levings, Megan K. 9 ; Steiner, Theodore 10 ; Sekirov, Inna 11 ; Zlosnik, James E. A. 6 ; Morshed, Muhammad 11 ; Skowronski, Danuta M. 7 ; Krajden, Mel 11 ; Jassem, Agatha N. 11 ; Sadarangani, Manish 1 

 University of British Columbia, Department of Pediatrics, Vancouver, Canada (GRID:grid.17091.3e) (ISNI:0000 0001 2288 9830); British Columbia Children’s Hospital Research Institute, Vaccine Evaluation Center, Vancouver, Canada (GRID:grid.414137.4) (ISNI:0000 0001 0684 7788) 
 British Columbia Children’s Hospital Research Institute, Vaccine Evaluation Center, Vancouver, Canada (GRID:grid.414137.4) (ISNI:0000 0001 0684 7788); University of British Columbia, Experimental Medicine Program, Vancouver, Canada (GRID:grid.17091.3e) (ISNI:0000 0001 2288 9830) 
 University of British Columbia, Department of Microbiology and Immunology, Vancouver, Canada (GRID:grid.17091.3e) (ISNI:0000 0001 2288 9830); British Columbia Children’s Hospital Research Institute, University of British Columbia, Vancouver, Canada (GRID:grid.17091.3e) (ISNI:0000 0001 2288 9830) 
 British Columbia Children’s Hospital Research Institute, Vaccine Evaluation Center, Vancouver, Canada (GRID:grid.414137.4) (ISNI:0000 0001 0684 7788); University of British Columbia, Department of Microbiology and Immunology, Vancouver, Canada (GRID:grid.17091.3e) (ISNI:0000 0001 2288 9830) 
 University of British Columbia, Department of Microbiology and Immunology, Vancouver, Canada (GRID:grid.17091.3e) (ISNI:0000 0001 2288 9830); British Columbia Children’s Hospital Research Institute, University of British Columbia, Vancouver, Canada (GRID:grid.17091.3e) (ISNI:0000 0001 2288 9830); University of Glasgow, Institute of Infection, Inflammation & Immunity, College of Medical, Veterinary and Life Sciences, Glasgow, UK (GRID:grid.8756.c) (ISNI:0000 0001 2193 314X) 
 British Columbia Centre for Disease Control, Vancouver, Canada (GRID:grid.418246.d) (ISNI:0000 0001 0352 641X) 
 British Columbia Centre for Disease Control, Vancouver, Canada (GRID:grid.418246.d) (ISNI:0000 0001 0352 641X); University of British Columbia, School of Population and Public Health, Vancouver, Canada (GRID:grid.17091.3e) (ISNI:0000 0001 2288 9830) 
 University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Department of Microbiology & Immunology, Melbourne, Australia (GRID:grid.1008.9) (ISNI:0000 0001 2179 088X); British Columbia Children’s Hospital Research Institute, University of British Columbia, Vancouver, Canada (GRID:grid.17091.3e) (ISNI:0000 0001 2288 9830); University of British Columbia, Department of Medicine, Vancouver, Canada (GRID:grid.17091.3e) (ISNI:0000 0001 2288 9830) 
 University of British Columbia, Department of Surgery, Vancouver, Canada (GRID:grid.17091.3e) (ISNI:0000 0001 2288 9830); University of British Columbia, School of Biomedical Engineering, Vancouver, Canada (GRID:grid.17091.3e) (ISNI:0000 0001 2288 9830); British Columbia Children’s Hospital Research Institute, University of British Columbia, Vancouver, Canada (GRID:grid.17091.3e) (ISNI:0000 0001 2288 9830) 
10  British Columbia Children’s Hospital Research Institute, University of British Columbia, Vancouver, Canada (GRID:grid.17091.3e) (ISNI:0000 0001 2288 9830); University of British Columbia, Department of Medicine, Vancouver, Canada (GRID:grid.17091.3e) (ISNI:0000 0001 2288 9830) 
11  University of British Columbia, Department of Pathology and Laboratory Medicine, Vancouver, Canada (GRID:grid.17091.3e) (ISNI:0000 0001 2288 9830); British Columbia Centre for Disease Control, Vancouver, Canada (GRID:grid.418246.d) (ISNI:0000 0001 0352 641X) 
Pages
8926
Publication year
2024
Publication date
2024
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
3041022682
Copyright
© The Author(s) 2024. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.