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Updated: Sep 10, 2025
A Suction Blister Protocol to Study Human T-cell Recall Responses In Vivo
Published on: August 11, 2018
High CD4⁺ T-cell responses in seronegative individuals following SARS-CoV-2 exposure during a dormitory outbreak
Ooiean Teng1, Amy May Lin Quek2, Delicia Shu Qin Ooi3
1Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
Objectives:
We studied individuals who remained uninfected by SARS-CoV-2 despite repeated exposures during a May-July 2020 dormitory outbreak in Singapore.
Methods:
We compared immune profiles of those with exposed seronegative (ESN) (negative PCR and serology), with noninfected and infected groups. Following the lifting of quarantine, incident infection rates were compared between the ESN and noninfected cohorts.
Results:
The immune profiles of 135 men with ESN (repeated negative PCR and persistent seronegativity), and 98 noninfected men, and 139 infected men were examined (mean age 33 years). Men with ESN exhibited higher percentages of CD4+T-cells and classical monocytes, alongside increased specific CD4+T cell responses to the nonstructural protein 12-3 region (NSP12-3) and spike peptides of SARS-CoV-2, compared with noninfection controls. Those with ESN did not differ in their IgG levels against endemic human coronaviruses compared with noninfection controls. Men in the ESN group were found to be less likely to become infected compared with noninfected controls (21% vs 39%, hazard ratio 0.47 [95% CI 0.27-0.73]) after the lifting of quarantine measures.
Conclusions:
These findings highlight the possible importance of cellular immunity in conferring partial resistance to infection and support the development of T-cell-focused strategies for high-risk settings.
Gov Number:
NCT04446104.
