Figure 4.

CD4 depletion does not affect protection but affects virus growth. Mice (n = 12/group) were vaccinated thrice i.n. with PBS (A,E), non-adjuvanted WIV (B,F), WIV+ CAF09 (C,G) or WIV+ CTA1-3M2e-DD (D,H) followed by heterosubtypic challenge. On day−1, 1 and 7 relative to the challenge, anti-CD4 antibody or PBS was administered i.p.. Mice were followed for 14 days for survival (A–D) and clinical symptoms (E–H). Dotted lines in E-H indicate the humane endpoint. Six animals/group were sacrificed on day 3 post challenge to determine lung virus titers (I). LoD is indicated by dashed line. Mock depletion is presented by filled symbols with—and CD4 depletion is represented by open symbols with +. Virus titers are represented as log₁₀ titers /gram of lung with level of significance as ^*p < 0.05 calculated using Mann-Whitney U-test.