Figure 4.

Measurement of PSMA specific serum antibodies. Mice were immunized 4 times at 4 weeks intervals by intramuscular injection with pCDNA3.1-PSMA or pCDNA3.1, antibody titers were measured by ELISA. Sera were serially diluted and measured individually. The experiment was performed in triplicate. Shown is the average antibody titer (n = 6) with standard errors. P valure was calculated by ANOVA. Antibody titer was similar in DNA vaccination group and CpG + DNA vaccination group, no antibody was detected in control group. * indicated the difference between control group with other two groups was statistically significant (P < 0.05).