FIG 6.

Enhanced protective immunity in CD47KO appears to reduce recall T cell responses. Immune cells were harvested from the BALF and lungs of vaccinated mice 6 dpi with A/PR8 influenza virus. (A and B) The cells producing IFN-γ were determined by culture for 5 h in the presence of HA peptides. Antigen-specific T cells were determined by intracellular cytokine staining with anti-IFN-γ antibodies. (C) Lung viral titers in the lungs. HA-VLP immune WT mice received either anti-CD8 depletion antibodies or PBS prior to A/PR8/34 (8 × LD₅₀) infection. The lung tissues were harvested at 6 dpi. Viral titers were determined by inoculation of chicken eggs with diluted lung samples. EID₅₀, 50% egg infectious dose. The statistical significance was determined by using one-way ANOVA. Error bars indicate the means ± the SEM of the concentrations or ratios from individual animals. *, P < 0.05; **, P < 0.01; NS, no significant difference.