Fig. 5
γ-PGA promotes influenza-specific CTL activity in mice with infected influenza virus. C57BL/6 mice (n = 5) were infected with PR8 and CA04 influenza viruses at 1 LD50 per mouse. After 24 h, mice were intranasally administrated with 100 μg of γ-PGA and 5 μg of CpG-ODN administrated prior to virus infection for 24 h. Nine days after infection, purified CD8+ T cells isolated from single-cell, lung suspensions of (a) PR8 and (b) CA04 virus infected mice were used as follows. To determine CTL activity, purified CD8+ T cells were mixed with target cells at an effector cell to target cell ratio of 50:1, and specific lysis values were quantified by performing lactate dehydrogenase release assays. For the ELISPOT assay, purified CD8+ T cells of (c) PR8 and (d) CA04 infected mice were stimulated with UV-inactivated influenza viruses and incubated for 72 h. Data are representative of two independent experiments with four to five replicate wells per group. Bars signify that test groups were significantly different from virus-alone groups when analyzed by t-test († indicates p < 0.01 compared to the virus infection group; *, p < 0.05 relative to the virus infection group)