Fig 1: Immune response of Ace2™ mice to B.1.1.529 infection. (A-F) 8-14-week-old Ace2™ mice were infected with Omicron and lung cells were harvested for flow cytometry at 3, 10, and 21 dpi. (A) Schematic of the infection and analysis protocol. (B) Frequency of neutrophils (CD11b+Ly6G+), macrophages (CD11b+F4/80+), dendritic cells (MHCII+CD11c+) and NK cells (NK1.1+) among total lung CD45+ cells from infected animals. (C) Frequency of CD4+ (TCRβ+CD4+) and CD8+ (TCRβ+CD8a+) T cells among total lung CD45+ cells. (D, E) Lung cells isolated at 10 and 21 dpi were stimulated with PMA and ionomycin for 4 hours prior cytokine staining. (D) Frequency of TNF-α+ (left), IFN-γ+ (center) and IL-17+ (right) CD4+ T cells. (E) Frequency of TNF-α+ (left), IFN-γ+ (right) CD8+ T cells. (F) Frequency of germinal center B cells (CD38low/–Fashi) in the mediastinal lymph node (mLN) of infected animals at 10 and 21 dpi (n = 3 mice per group). Data were analyzed by one-way ANOVA.