FIG. 2.

Recombinant vaccinia virus expressing UL6 protein fails to induce reactivity to HSV or G2a peptide. Groups of B/c mice (n = 6) were infected with 2 × 10⁶ PFU of vaccinia virus expressing UL6 (Vac UL6) on scarified corneas. At day 14 postinfection mice were sacrificed, and pooled popliteal lymph nodes and individual splenocytes were used as responders in a lymphoproliferation assay (A) and an IFN-γ cytokine ELISA (B) as described in Materials and Methods. Responders were stimulated with irradiated syngeneic splenocytes pulsed with UV-irradiated vaccinia virus (MOI = 5.0), UV-irradiated HSV (MOI = 5.0), and the UL6, G2a, and HA peptides (10, 1.0, and 0.1 μg/ml). The data represent peptide stimulation with a 10-μg/ml concentration. The polyclonal stimulator, ConA (2 μg/ml), was used as a positive control (data not shown). The results of two independent experiments are expressed as the means ± the standard deviations. Statistically significant differences within groups (∗∗, P < 0.001) and between groups (∗, P < 0.05) are indicated.