FIG. 6.

Histopathologic changes in the lungs of SARS-CoV-infected mice at day 9 p.i. (A) Mice were treated with isotype control Ab (a and b), anti-CD8 (c and d), anti-CD4 (e and f), and anti-CD4 and CD8 Ab (g and h) as described in Materials and Methods. Compared to isotype control-treated mice (a), perivascular lymphocytic infiltrates are diminished in mice by treatment with anti-CD8 (c), anti-CD4 (e), and anti-CD4 and CD8 Ab (g) MAbs. Multifocal interstitial infiltrates are identified in the lungs of all infected mice (b, d, f, and h) but are most prominent in the mice depleted of CD4⁺ T cells (f). (B) Pathology scores of pulmonary inflammation in the lungs were assessed on day 9 p.i. Data represent means ± SEMs for four mice at the indicated time point.