Researchers in Portugal have provided evidence that might explain why infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes mild or even asymptomatic illness in some individuals, but severe coronavirus disease 2019 (COVID-19) in others.
Salome Pinho from the University of Porto and colleagues showed that circulating T cells exhibit a specific “glycan switch” following infection with SARS-CoV-2 and that this switch is more pronounced in asymptomatic versus symptomatic individuals.
The researchers say this change in the T cell glycosylation profile appears to be triggered by a serum inflammatory factor, the identification of which could lead to a potential new biomarker and therapeutic target.
The team also demonstrated that circulating monocytes in asymptomatic patients exhibit up-regulated expression of a protein called Dendritic Cell-Specific Intercellular adhesion molecule-3-Grabbing Non-integrin (DC-SIGN).
Furthermore, a higher level of DC-SIGN expression in monocytes was correlated with a better patient prognosis.
“These new findings pave the way for identification of a novel glycan-based response in T cells that may confer protection against SARS-CoV-2 infection in asymptomatic patients, highlighting a novel prognostic biomarker and potential therapeutic target,” writes the team…