gene expression profile of lung immune cells isolated from mock- or SARS-CoV-2 infected mice at single cell level

Aging is one of the greatest rick factor of COVID-19. We use single cell RNA sequencing to compare the immune responses in the lung bewteen aged (19-month-old) and young (3-week-old) mice. 3-week or 19-month-old C57BL/6J mice were mock infected or infected with a mouse adapted SARS-CoV-2 virus. At three days post-infection, lungs were harvested from three mice from each group,pooled for digestion with enzyme mix ( Liberase, 33.3 μg/mL, and DNaseI 133.3 ug/mL ) at at 37 ℃ for 30 min with rotation. The released cells were subjected to red blood cell lysis. 12,000 cells from each group were loaded in the lane with 10x Chromium (10x Genomics, USA) for single cell sequencing following the instructions of the Chromium Single Cell 3′ Reagent Kit v3 .