Fig. 1.

Determinants of illness in vvGs-immunized mice. The mice were immunized with vac-lac or vvGs by intradermal injection at the base of the tail 5 × 10⁵ plaque-forming units (pfu) in 0.05 ml PBS of vvGs. Six weeks after immunization mice were challenged with 1 × 10⁷ pfu (in 0.1 ml) live respiratory syncytial virus (RSV), and then the mice were weighed daily to assess illness. (A) Weight loss in mice that were depleted of CD4+, CD8+, or both CD4+ and CD8+ T cells at the time of vvGs immunization by intraperitoneal (IP) administration of specific antibodies on days –1, 0, and 1 of priming (0.2 mg per injection) is depicted. (B) Weight loss in mice depleted of IL-5 at immunization or at challenge by intraperitoneal injection of anti-IL5-specific antibodies at days –2, –1, 0, 1, and 2 of immunization or challenge (0.2 mg of antibody per injection) is illustrated. (C) Weight loss in eotaxin-1 deficient mice is shown. The weight loss is shown as percentage of baseline weight. The data represent mean ± sd for n = 15 mice from 3 separate experiments (A and B) and n = 5 from a single experiment (C). All data were maintained in a Paradox database and analyzed by ANOVA using SAS software. Differences were considered to be significant when P < 0.05. Significant differences are denoted by * (vvGs-immunized mice depleted of CD4 at priming (A) or IL-5 at challenge (B) had significant improvement in weight loss relative to isotype control-treated vvGs-immunized mice); ^#, (CD4+CD8-depleted vvGs-immunized mice had significant improvement in weight loss relative to isotype control-treated mice); and ** (vvGs-immunized mice significantly increased relative to vac-lac-immunized mice).