Fig 1: BAFF-R–positive cells are increased in NALT by IFN-a administration or age in NALT upon primary infection with RSV. BAFF-R–positive cells by flow cytometry in NALT and lungs from RSV-infected adult (AR) and neonatal mice receiving IFN-a (INR) or placebo (NR) 16 h before RSV infection and adult (ARR) and neonatal mice receiving IFN-a (INRR) or placebo (NRR) 16 h before RSV infection and reinfected 4 weeks after primary infection. (a) Representative flow cytometry panels of B220+CD19+BAFF-R+ cells. (b–f) Percentage of B220+CD19+BAFF-R+ cells at different time points. (b) 7 dpi; (c) 14 dpi; (d) 21 dpi; (e) 7 days post-secondary infection in NALT; (f) 7 days post-secondary infection in lungs. (g) IHC analysis demonstrating expression of BAFF-R protein in NALT and lungs of RSV-challenged groups and control mice at 7, 14, and, 21 days post infection, as well as, after reinfection. Magnification 200×; scale bar = 100 µm. n = 3–5; N = 2 *P < 0.05, **P < 0.01.