FIG 3.

Immunization with different time intervals between prime and boost. C57BL/6 mice were immunized with 10⁶ IU of VREP-OVA and given a homologous boost 1, 3, 6, or 9 weeks later. Each immunized group consisted of eight mice, and the naive group consisted of three mice. (A) Mice were sacrificed, spleens were collected, and SIINFEKL-specific CD8⁺ T cells were assessed by IFN-γ ELISPOT at 5 days (left) or 5 weeks (right) postboost. Lines represent medians. *, P < 0.05; **, P < 0.01. (B and C) At 5 weeks postboost, pentamer⁺ CD8⁺ T cells and proportions of these cells that expressed CD62L/CD127 or CD27/CD43 were also assessed by flow cytometry in splenocytes (B) and peripheral blood (C) from mice boosted 1 or 9 weeks after primary immunization. Two independent experiments were performed; the results shown are from one representative experiment.