γ-PGA inhibits MNV-1 in mice. BALB/c mice (6 weeks old, n = 7–8 per group) were administered with 2,000-kDa γ-PGA as described in Fig. 4 for 5 days. Twelve hours after the last γ-PGA administration, mice were inoculated with MNV-1 (1 × 107 PFU in 100 µl saline) perorally and given γ-PGA once daily for another two days. Viral genome and infectious virus titers in the ileum with PPs and the MLNs were determined by RT-qPCR (a) and plaque-forming assay (b), respectively. In all panels, data are mean ± s.d. *P < 0.05 by two-tailed unpaired Student’s t-test.