{Reference Type}: Journal Article
{Title}: Dynamic anti-spike protein antibody profiles in COVID-19 patients.
{Author}: Bao Y;Ling Y;Chen YY;Tian D;Zhao GP;Zhang XH;Hang H;Li Y;Su B;Lu HZ;Xu J;Wang Y;
{Journal}: Int J Infect Dis
{Volume}: 103
{Issue}: 0
{Year}: Feb 2021
{Factor}: 12.074
{DOI}: 10.1016/j.ijid.2020.12.014
{Abstract}: <B>OBJECTIVE: </B>This study intended to investigate the dynamics of anti-spike (S) IgG and IgM antibodies in COVID-19 patients.<BR><B>METHODS: </B>Anti-S IgG/IgM was determined by a semi-quantitative fluorescence immunoassay in the plasma of COVID-19 patients at the manifestation and rehabilitation stages. The immunoreactivity to full-length S proteins, C-terminal domain (CTD), and N-terminal domain (NTD) of S1 fragments were determined by an ELISA assay. Clinical properties at admission and discharge were collected simultaneously.<BR><B>RESULTS: </B>The positive rates of anti-S IgG/IgM in COVID-19 patients were elevated after rehabilitation compared to the in-patients. Anti-S IgG and IgM were not apparent until day 14 and day ten, respectively, according to Simple Moving Average analysis with five days' slide window deduction. More than 90% of the rehabilitation patients exhibited IgG and IgM responses targeting CTD-S1 fragments. Decreased total peripheral lymphocytes, CD4+ and CD8+ T cell counts were seen in COVID-19 patients at admission and recovered after the rehabilitation.<BR><B>CONCLUSIONS: </B>Anti-S IgG and IgM do not appear at the onset with the decrease in T cells, making early serological screening less significant. However, the presence of high IgG and IgM to S1-CTD in the recovered patients highlights humoral responses after SARS-CoV-2 infection, which might be associated with efficient immune protection in COVID-19 patients.