FIG. 3.

Effect of T-cell depletion on survival of H3N2-immune mice. Groups of mice were vaccinated with H3N2 in the presence of LT(R192G) as described in Materials and Methods. The adjuvant control mice received LT(R192G) only (●). Mice received 1 mg of the anti-CD4 (○), anti-CD8 (◊), a combination of both MAbs (anti-CD4/CD8) (□), or rat IgG (▵) control antibody on days −2, +2, +6, and +10 relative to the time of challenge. Mice were challenged i.n. with a lethal dose of H5N1 and were monitored for survival (A) or euthanatized for collection of tissues on day 5 (B). Individual lung and brain tissues were titrated for virus infectivity as described in the legend to Fig. 1. An asterisk indicates the T cell-depleted group was significantly (P < 0.05) different from the rat IgG control group by analysis of variance.