Abstract
It is important to evaluate the durability of the protective immune response elicited by primary infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we systematically evaluated the SARS-CoV-2-specific memory B cell and T cell responses in healthy controls and individuals recovered from asymptomatic or symptomatic infection approximately 6 months prior. Comparatively low frequencies of memory B cells specific for the receptor-binding domain (RBD) of spike glycoprotein (S) persisted in the peripheral blood of individuals who recovered from infection (median 0.62%, interquartile range 0.48-0.69). The SARS-CoV-2 RBD-specific memory B cell response was detected in 2 of 13 individuals who recovered from asymptomatic infection and 10 of 20 individuals who recovered from symptomatic infection. T cell responses induced by S, membrane (M), and nucleocapsid (N) peptide libraries from SARS-CoV-2 were observed in individuals recovered from coronavirus disease 2019 (COVID-19), and cross-reactive T cell responses to SARS-CoV-2 were also detected in healthy controls.
Highlights
Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) infection[1], is a global pandemic, with more than 102 million infections and more than 2,209,000 deaths as of 1 Feb 2021, according to the COVID-19 report of the World Health Organization
Twenty individuals recovered from COVID-19 with symptoms (RS), 13 individuals recovered from asymptomatic infection (RA), and 10 healthy controls (HC) were recruited in this study (Supplemental Table S1)
SARS-CoV-2-specific IgG turned negative in 3 of the 13 individuals who recovered from asymptomatic infection, while 2 of the 20 individuals who recovered from symptomatic infection showed seronegative characteristics, as measured by the current chemiluminescent immunoassay (CLIA) (23.1% vs 10%, P = 0.360)
Summary
Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) infection[1], is a global pandemic, with more than 102 million infections and more than 2,209,000 deaths as of 1 Feb 2021, according to the COVID-19 report of the World Health Organization. The clinical manifestations of SARS-CoV-2 infection range from asymptomatic disease or mild symptoms to severe pneumonia, acute respiratory distress syndrome (ARDS), and even death[2]. Adaptive immunity[3], including humoral and cellular immune responses, has been proven to be a crucial step in viral infection control. Specific memory B cell responses to variola virus, varicella-zoster, measles, and mumps were estimated to persist over 50 years[14]. Other viral infections, such as influenza[15] and respiratory syncytial virus (RSV)[16], confer a waning immunological memory response. For recovered SARS-CoV infection patients followed up for 6 years, there was no peripheral memory B cell response[17]. There is scattered evidence of reinfection by SARS-CoV-218,19, and reinfections by natural infection occur for all four seasonal coronaviruses[20]
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