Time course of total and differential cell counts in BAL fluid after administration of 10 μM CpG-ODN. (A) Total cell counts in BAL fluid were markedly increased 24 h after CpG-ODN challenge and then decreased by 14 days after the instillation. (B) Neutrophil counts on days 1 and 2 were significantly greater than in the animals that received the control ODN or PBS. (C) Lymphocyte counts in BAL fluid were significantly increased on days 2 and 7 compared with the mice treated with the control ODN or PBS. Values are the mean ± SEM; n = 5-6 for each group. *p < 0.05 compared with the PBS group. †p < 0.05 compared with the control ODN group.