RT Journal Article
SR Electronic
T1 Comparison of T-cell immune responses to SARS-CoV-2 spike (S) and nucleocapsid (N) protein using an in-house flow-cytometric assay in laboratory employees with and without previously confirmed COVID-19 in South Africa: nationwide cross-sectional study
JF Journal of Clinical Pathology
JO J Clin Pathol
FD BMJ Publishing Group Ltd and Association of Clinical Pathologists
SP 384
OP 390
DO 10.1136/jclinpath-2021-207556
VO 76
IS 6
A1 Cathrine van Rooyen
A1 Marieke Brauer
A1 Petri Swanepoel
A1 Sylvia van den Berg
A1 Cassandre van der Merwe
A1 Marischa van der Merwe
A1 Robin Green
A1 Piet Becker
YR 2023
UL http://jcp.bmj.com/content/76/6/384.abstract
AB Aims To compare specific T-cell responses between laboratory employees in South Africa with and without previously diagnosed SARS-CoV-2 infection.Methods Employees at a private pathology laboratory in South Africa were invited to participate in a nationwide cross-sectional study. T-cell proliferation to SARS-CoV-2 nucleocapsid (N)-proteins and spike (S)-proteins was measured by flow cytometry and compared between participants.Results Based on classification according to SARS-CoV-2 reverse transcription (RT)-PCR results, a total of 81% (42/52) of positive participants demonstrated T-cell proliferation to SARS-CoV-2 N-proteins or S-proteins (95% CI 67.5% to 90.4%), while 62% (68/110) of negative participants also had detectable T-cell responses to SARS-CoV-2 proteins (95% CI 52.1% to 70.9%). When classified according to SARS-CoV-2 serology results, 92.6% (50/54) of positive participants demonstrated T-cell proliferation to SARS-CoV-2 proteins (95% CI 82.1 to 97,9 %), while 56% (60/108) of negative participants demonstrated T-cell proliferation (95% CI 45.7% to 65.1%). The magnitude of the T-cell responses as determined by a stimulation index, was significantly higher in the group previously infected by SARS-CoV-2 than in the negative group. A statistically significant difference in T-cell proliferation was noted between high risk and low risk groups for exposure to SARS-CoV-2 within the negative group, but no significant difference in magnitude of the response.Conclusions A significant proportion of South African laboratory employees who were not previously diagnosed with COVID-19 demonstrated T-cell reactivity to SARS-CoV-2 N-proteins and S-proteins. The pre-existing T-cell proliferation responses may be attributable to cross-reactive immune responses to other human coronaviruses, or possibly asymptomatic infection.All data relevant to the study are included in the article or uploaded as online supplemental information. Deidentified participant data available as online supplemental information.