FIG. 5.

Immunization with V peptides encoding CD4 T-cell epitopes primes antigen-specific type 1 memory CD4 T-cell responses. C57BL/6 mice were immunized with peptides V1, V2, V3, or Vneg emulsified in CFA. Thirty days later, mice were reimmunized with the same peptides emulsified in IFA. On day 60 after the primary immunization, memory CD4 T-cell responses were assessed by measuring the in vitro production of IL-2 (A) or IFN-γ (B) by ELISA, as in Fig. 1. In addition, the number of IFN-γ-producing cells was measured by ELISPOT assay using triplicate determinations for each sample (C). P values were <0.01 (*) and <0.001 (**) compared with each of the other values within an immunization group. Data are representative of results obtained in three independent experiments.