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Title: Prevalence and functional profile of SARS-CoV-2 T cells in asymptomatic Kenyan adults
Authors: 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
Dutertre, Charles-Antoine
Tan, Nicole
Hang, Shou Kit
Hariharaputran, Smrithi
Lye, David C.
Herman-Roloff, Amy
Le Bert, Nina
Bertoletti, Antonio
Keywords: Science::Medicine
Issue Date: 2023
Source: Samandari, T., Ongalo, J. B., McCarthy, K. D., Biegon, R. K., Madiega, P. A., Mithika, A., Orinda, J., Mboya, G. M., Mwaura, P., Anzala, O., Onyango, C., Oluoch, F. O., Osoro, E., Dutertre, C., Tan, N., Hang, S. K., Hariharaputran, S., Lye, D. C., Herman-Roloff, A., ...Bertoletti, A. (2023). Prevalence and functional profile of SARS-CoV-2 T cells in asymptomatic Kenyan adults. Journal of Clinical Investigation, 133(13), e170011-.
Project: COVID19RF3-0060 
Journal: Journal of Clinical Investigation 
Abstract: Background: SARS-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. Methods: We 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. Results: Among 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. Conclusions: The 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.
ISSN: 0021-9738
DOI: 10.1172/JCI170011
Schools: Lee Kong Chian School of Medicine (LKCMedicine) 
Organisations: National Centre for Infectious Diseases, Singapore 
Tan Tock Seng Hospital 
Yong Loo Lin School of Medicine, NUS 
Rights: © 2023 Samandari et al. This is an open access article published under the terms of the Creative Commons Attribution 4.0 International License.
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:LKCMedicine Journal Articles

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