Prevalence and functional profile of SARS-CoV-2 T cells in asymptomatic Kenyan adults
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Date
2023Author
Samandari, Taraz
Ongalo, Joshua B
McCarthy, Kimberly D
Biegon, Richard K
Madiega, Philister A
Mithika, Anne
Orinda, Joseph
Mboya, Grace M
Mwaura, Patrick
Anzala, Omu
Onyango, Clayton
Oluoch, Fredrick O
Osoro, Eric
Charles-Antoine, Dutertre
Tan, Nicole
Hang, Shou Kit
Hariharaputran, Smrithi
Lye, David C
Amy, Herman-Roloff
Bert, Nina Le
Bertoletti, Antonio
Type
ArticleLanguage
enMetadata
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BackgroundSARS-CoV-2 infection in Africa has been characterized by a less severe disease profile than what has been observed elsewhere, but the profile of SARS-CoV-2-specific adaptive immunity in these mainly asymptomatic patients has not, to our knowledge, been analyzed.MethodsWe collected blood samples from residents of rural Kenya (n = 80), who had not experienced any respiratory symptoms or had contact with individuals with COVID-19 and had not received COVID-19 vaccines. We analyzed spike-specific antibodies and T cells specific for SARS-CoV-2 structural (membrane, nucleocapsid, and spike) and accessory (ORF3a, ORF7, ORF8) proteins. Pre-pandemic blood samples collected in Nairobi (n = 13) and blood samples from mild-to-moderately symptomatic COVID-19 convalescent patients (n = 36) living in the urban environment of Singapore were also studied.ResultsAmong asymptomatic Africans, we detected anti-spike antibodies in 41.0% of the samples and T cell responses against 2 or more SARS-CoV-2 proteins in 82.5% of samples examined. Such a pattern was absent in the pre-pandemic samples. Furthermore, distinct from cellular immunity in European and Asian COVID-19 convalescents, we observed strong T cell immunogenicity against viral accessory proteins (ORF3a, ORF8) but not structural proteins, as well as a higher IL-10/IFN-γ cytokine ratio profile.ConclusionsThe high incidence of T cell responses against different SARS-CoV-2 proteins in seronegative participants suggests that serosurveys underestimate SARS-CoV-2 prevalence in settings where asymptomatic infections prevail. The functional and antigen-specific profile of SARS-CoV-2-specific T cells in African individuals suggests that environmental factors can play a role in the development of protective antiviral immunity.FundingUS Centers for Disease Control and Prevention, Division of Global Health Protection; the Singapore Ministry of Health's National Medical Research Council (COVID19RF3-0060, COVID19RF-001, COVID19RF-008, MOH-StaR17Nov-0001).
Citation
Samandari T, Ongalo JB, McCarthy KD, Biegon RK, Madiega PA, Mithika A, Orinda J, Mboya GM, Mwaura P, Anzala O, Onyango C, Oluoch FO, Osoro E, Dutertre CA, Tan N, Hang SK, Hariharaputran S, Lye DC, Herman-Roloff A, Le Bert N, Bertoletti A. Prevalence and functional profile of SARS-CoV-2 T cells in asymptomatic Kenyan adults. J Clin Invest. 2023 Jul 3;133(13):e170011. doi: 10.1172/JCI170011. PMID: 37219944; PMCID: PMC10313370.Publisher
University of Nairobi
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Attribution-NonCommercial-NoDerivs 3.0 United StatesUsage Rights
http://creativecommons.org/licenses/by-nc-nd/3.0/us/Collections
- Faculty of Health Sciences (FHS) [10378]
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