FIG 4.
Immunization with UV-V and TLR agonists inhibits excessive eosinophilic infiltration after SARS-CoV challenge. Adult female BALB/c mice were vaccinated with UV-V, UV-V with TLR agonists (UV-V+TLR), or vehicle (PBS) and subsequently challenged with 1,000 TCID50 of F-musX. Dead mice are marked with crosses. (A and B) Mice were weighed daily and monitored for morbidity (n = 6 to 7). (C) SARS-CoV titers in the lungs and lung wash fluids 3 days after intranasal challenge with SARS-CoV (n = 4). Significant differences (P < 0.05, one-way ANOVA) between groups are marked with an asterisk. The dashed line indicates the limit of detection (101.5 TCID50/ml). Error bars indicate standard deviations. LW, lung wash fluid. (D) SARS-CoV-specific neutralizing serum antibody titers 52, 10, and 0 days before challenge (n = 13 to 14) and 3 and 10 days after challenge (n = 6 to 7, respectively) with SARS-CoV. Serum samples were 2-fold serially diluted beginning at 1:2. Error bars indicate standard deviations. (E) Representative images of lung sections from mice immunized with UV-V, UV-V+LPS, or UV-V+TLR on days 3 and 10 after challenge with F-musX. Hematoxylin-and-eosin (magnification, ×10) and C.E.M. kit (inset magnification, ×100) staining was used. Br, bronchi; *, blood vessel. (F) Numbers of lymphocytes, macrophages, neutrophils, and eosinophils in the lung sections (n = 3). Five 240-μm2 regions in the extrabronchioles of lung per mouse were examined at magnification ×40. Asterisks indicate P < 0.05 by the Bonferroni test. Error bars indicate standard deviations.