COVID-19 patients display distinct SARS-CoV-2 specific T-cell responses according to disease severity

Abstract

Adaptive Immune responses generated by SARS-CoV-2 virus in convalescent patients according to disease severity remain poorly characterized. To this end, we designed a prospective study (NCT04365322) that included 60 COVID-19 convalescent patients (1-month post infection) in two cohorts respectively entitled mild illness and severe pneumonia. The monitoring of peripheral immune responses was performed using IFNᵧ ELISpot assay. The serology index of each patient was investigated at the same time. Patients with severe pneumonia were older and had more comorbidities than patients with mild illness. T-cell responses in term of frequency and intensity were clearly distinct between mild illness and severe pneumonia patients. Furthermore, our results demonstrated that recent history of COVID-19 did not hamper viral memory T-cell pool against common viruses (Cytomegalovirus, Epstein-Barr-virus and Flu-virus). The presence of potent adaptive immunity even in patients who underwent severe pneumonia sustain the rationale for the development of protective therapeutics against SARS-CoV-2.

Keywords: Adaptive immunity; COVID-19; Coronavirus; Interferonᵧ; SARS-CoV-2; T-cells.

Conflict of interest statement

Declaration of Competing Interest Authors declare no competing financial interests.

Copyright © 2020 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

Figures

Fig. 1

SARS-CoV-2 specific T-cell responses were increased in mild illness compared to severe pneumonia COVID-19 patients. A. PBMC from 21 healthy donors and COVID-19 patients with mild illness (n = 29) or severe pneumonia (n = 30) were analyzed for SARS-CoV-2 and antiviral-specific T-cell responses by IFNᵧ ELISpot assay. B. Intensity of positive SARS-CoV-2 specific immune responses in healthy donors and COVID-19 patients. Mann Whitney test, **P>0.001. Median with interquartile range were indicated. C. Heatmap showing the positivity or the negativity of the serology index, T-cell immune responses to SARS-CoV-S, M and N proteins for each patients included in the study (online Morpheus software). D. Frequency of patients with a specific T-cell response for at least one SARS-CoV-2 proteins (CoV-S, CoV-M or CoV-N) (P = 0.0211). E. Frequency of mild illness and severe pneumonia patients with specific T-cell responses for simultaneously CoV-S, CoV-M and CoV-N proteins (P = 0.0191). F. Frequency (%) of positive antiviral memory CD8T-cell responses for healthy donors, mild illness and severe pneumonia COVID-19 convalescent patients. Healthy donors were represented by light gray points. COVID-19 convalescent patients were respectively represented by black point (mild illness) and red points (severe pneumonia). PBMC: Peripheral Blood Mononuclear Cells.