Journal: Journal of Clinical Pathology

Article Title: 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

doi: 10.1136/jclinpath-2021-207556

Figure Lengend Snippet: Flow cytometric gating strategies used to identify the response of T-cells to the N-protein and S-protein of SARS-CoV2. Gating was first set on singlet events (A), followed by gating on target populations, leucocytes (B) and then CD3 expressing T-cells (C). The stimulation of the T-cells were measured using intracellular—PE Ki-67 (D). Buffer was added to the negative control (unstimulated) in (D). The positive control in (E) was pokeweed mitogen. The stimulation of the T-cells can be seen in the proliferation gate (E). T-cell activation seen in the proliferation gate (F) when exposed to nucleocapsid (N) protein of SARS-CoV2. T-cell activation seen in the proliferation gate (G) when exposed to spike (S) protein of SARS-CoV2. SSC, side scatter.

Article Snippet: A standardised, in-house flow cytometric lymphocyte proliferation test method currently in use at Ampath to detect T-cell responses to other recall antigens, for example, Varicella-Zoster-Virus (VZV), Candida albicans and Tetanus toxoid was modified for the purpose of this study.

Techniques: Expressing, Negative Control, Positive Control, Activation Assay