Host immunity helps the body to fight against COVID-19. Single-cell transcriptomics has provided the scope of investigating cellular and molecular underpinnings of host immune response against SARS-CoV-2 infection at high resolution. In this review, we have systematically described the virus-induced dysregulation of relative abundance as well as molecular behavior of each innate and adaptive immune cell type and cell state during COVID-19 infection and for different vaccinations, based on single-cell studies published in last three-four years. Identification and characterization of these disease-associated specific cell populations might help to design better, efficient, and targeted therapeutic avenues.
Keywords: COVID-19; Cell states; SARS-CoV-2; cell types; host immunity; single-cell; vaccines.
SARS-CoV-2 infection and the resulting COVID-19 extensively affects the body’s immune system. Recent single-cell transcriptomic studies have elucidated the changes of the immune system in both the proportion and function of different immune cell types in SARS-CoV-2 infection as well as in vaccination. Inflammation was found to be driven by an increase in specific immune cell types, while a decrease in others were observed to weaken the body’s ability to fight the virus. We have discussed these studies and their findings in this review. We have also shown how these findings suggest coordination between T and B cells is a key factor in generation of immune responses against the virus and how high levels of immune signaling molecules and antibodies in severe cases led to poor outcomes. These insights could help guide the development of improved targeted treatments of COVID-19 as well as similar viruses for fast and efficient cure.