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Holder K, Hatfield K, Ings D, Fifield K, Harnum D, Grant M. Antibody ‘Hotspots’ induce antibody-dependent cell-mediated cytotoxicity against SARS-CoV-2 spike-expressing lung fibroblasts. The Journal of Immunology 2022. [DOI: 10.4049/jimmunol.208.supp.50.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
Since COVID-19 emerged in 2019, neutralizing antibody (Ab) responses have dominated as surrogate measures of protection against infection and severe illness. The mostly self-limiting course of SARS-CoV-2 infection suggests the innate immune system, including natural killer (NK) cells, plays a role in its control. Therefore, we investigated SARS-CoV-2-specific antibody-dependent cell-mediated cytotoxicity (ADCC) and if Abs against Wuhan and early SARS-CoV-2 variants activate ADCC against emergent highly transmissible variants. ADCC was evaluated by measuring NK cell cytotoxicity (51Cr) against plasma (1:1000)-sensitized MRC-5 cells stably transduced to express Wuhan or Delta spike. ADCC mediated by plasma from double-vaccinated and convalescent adults was generally low (range 1.2 – 24.9%; median 7.2% (IQR 5.2 – 10.6%), and plasma from those with previous natural infection mediated significant ADCC (> 10% lysis) to the same extent as plasma from fully vaccinated individuals (13/34 vs 11/44). Hybrid immunity imparted robust ADCC (27.9 ± 10.8% target lysis) in 32/34 individuals tested and levels of ADCC significantly correlated with IgG3 responses (P = 0.0093) against spike stalk (S2) domain. A peptide scan identified four distinct ‘hotspot’ regions associated with robust ADCC in individuals with reactive Abs. Overall, a minor decline in ADCC against Delta variant spike-expressing relative to Wuhan targets occurred in all groups; however, individuals with Abs against the region containing D614G mediated greater ADCC against Delta variant than Wuhan targets. Determining which Abs provide robust and broad ADCC can inform future COVID-19 prevention and treatment strategies and predict ADCC responses for emergent variants.
Supported by grants from CIHR through the COVID Immunity Task Force (VR1-173202)
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Affiliation(s)
- Kayla Holder
- 1BioMedical Sciences, Memorial University of Newfoundland, Canada
| | - Keeley Hatfield
- 1BioMedical Sciences, Memorial University of Newfoundland, Canada
| | - Danielle Ings
- 1BioMedical Sciences, Memorial University of Newfoundland, Canada
| | - Katie Fifield
- 1BioMedical Sciences, Memorial University of Newfoundland, Canada
| | | | - Michael Grant
- 1BioMedical Sciences, Memorial University of Newfoundland, Canada
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