Inhibition of E7-specific IgG and IgG2b production by the E7 DNA vaccine regimen (E7 DNA vaccine+IL-2 cDNA) plus anti-4-1BB Abs.

<p>Each group of mice (n = 6–8) was challenged s.c. with 2×10⁵ TC-1 cells per mouse. When the tumor sizes reached approximately 5 mm, the mice were treated by IM-EP with 50 µg of E7 DNA vaccines plus 10 µg of IL-2 cDNA (pE7+pIL-2) at 0, 4 and 11 days. The animals were also injected i.p. with 100 µg of anti-4-1BB and control rat Abs at 0, 1 and 2 weeks. The mice were bled at 11 days following the last anti-4-1BB Ab injection, and sera in each group were equally pooled and diluted to 1∶100 for reaction with E7 proteins for ELISA. Samples were assayed in triplicate. The values of E7-specific IgG (A) and IgG subclasses (B), and bars represent the mean optical density and SD, respectively. (C) The IgG2b/IgG1 ratio was calculated by dividing the mean optical density of IgG2b by that of IgG1. *p<0.05 using one-way ANOVA compared to pcDNA3. **p<0.05 using one-way ANOVA compared to pE7+pcDNA3.