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http://ir.mu.ac.ke:8080/jspui/handle/123456789/7561
Title: | Prevalence and functional profile of SARS-CoV-2 T cells in asymptomatic Kenyan adults |
Authors: | Samandari, Taraz Ongalo, Joshua McCarthy, Kim Biegon, Richard K. Madiega, Philister Mithika, Anne Orinda, Joseph Mboya, Grace M. Mwaura, Patrick Anzala, Omu |
Keywords: | SARS-CoV-2 Asymptomatic |
Issue Date: | 2023 |
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 cases has not been analyzed. Methods. We collected samples of residents of rural Kenya (n=80) who had not experienced any respiratory symptoms nor had contact with COVID-19 cases or 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 samples collected in Nairobi (n=13) and samples of mild-moderately symptomatic COVID-19 convalescents (n=36) living in the urban environment of Singapore were also studied. Results. Among asymptomatic Africans, we detected anti-spike antibodies in 41.0% and T cell responses against ≥2 SARS-CoV-2 proteins in 82.5%. Such a pattern was absent in pre-pandemic samples. Furthermore, distinct from cellular immunity in European and Asian COVID-19 convalescents, strong T cell immunogenicity was observed against viral accessory proteins (ORF3a, ORF8) and not structural proteins, as well as a higher IL-10/IFN-γ ratio cytokine profile. Conclusions. The high incidence of T cell response 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. Fundings. U.S. Centers for Disease Control and Prevention, Division of Global Health Protection; the Singapore Ministry of Health’s National Medical Research Council. |
URI: | https://doi.org/10.1172/JCI170011 http://ir.mu.ac.ke:8080/jspui/handle/123456789/7561 |
Appears in Collections: | School of Medicine |
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