UMAP-based dimensionality reduction plot denoting cell types (A, C, E) and corresponding expression levels of ACE2, DPP4, ANPEP and TMPRSS2 (B, D, F) from multiple tissues in the Tabula Muris study (Tabula Muris Consortium et al., 2018): (A–B) spleen, (C–D) bone marrow, (E–F) thymus.