Immunogenicity of EGFRvIII vaccine candidates.

a) EGFRvIII26-33 -specific CD8+ T cell responses in C3H mice vaccinated with Lm-EGFRvIIIx1 or Lm-EGFRvIIIx5, determined by IFN-γ ICS on day 7. b) Primary immunogenicity of PEPvIII and Lm-EGFRvIIIx5 in C3H mice, represented as the frequency of Kk-EGFRvIII26-33 -tetramer+ cells within the CD3+CD8+ T cell population. c) 21 days after immunization with Lm-EGFRvIIIx5 or a 3 dose regimen of PEPvIII, the frequency of Kk-EGFRvIII26-33 -tetramer+ cells within the CD3+CD8+ T cell population was determined. d) C3H mice were vaccinated x3 with PEPvIII, or a single dose of Lm-EGFRvIIIx5 as indicated. 21 days after the last vaccination, mice were boosted with PEPvIII or Lm-EGFRvIIIx5. Five days later, the frequency of Kk-EGFRvIII26-33 -tetramer+ cells within the CD3+CD8+ T cell population was determined. Each symbol represents one animal. Bars represent mean ± SEM of groups containing 4–5 animals. Each figure represents a single experiment from a minimum of two replicates. (ANOVA).