FIG. 5.

Lymphocyte proliferation activity in spleens of mice immunized with recombinant viruses. BALB/c mice were immunized three times with vP35, vP40, vIL-4, dbl-p, or KOS or were mock immunized as described in Materials and Methods. Spleens were collected 3 weeks after the third immunization. Splenocytes were primed in vitro for 72 h, and cells were labeled with [³H]thymidine for 24 h as described in Materials and Methods. Each point represents mean ± the SEM from three experiments.