Vaccination with scFvNLDC-145-HER2 induced HER2-specific antibodies. BALB/c mice were vaccinated with HER2, scFvNLDC-145-neu or scFvNLDC-145-HER2. Control animals received PBS or pcDNA3.1. Sera were collected from the vaccinated animals after two vaccinations. A HER2-specific total IgG and IgG subclass (IgG1and IgG2a) antibodies in sera from the vaccinated animals after 1:100 dilution were determined by ELISA. The mean OD405 values of pooled sera from each group (5 mice per group) were presented. Bars, SE. The background OD405 of normal mouse sera was < 0.04. B D2F2/E2 cells were incubated with the immune sera obtained from the vaccinated animals, and surface bound antibodies were detected using FITC-labeled secondary antibodies. Samples were then analyzed by flow cytometry. The data were represented as mean fluorescence intensity. Normal mouse sera served as control. All results were representative of two independent experiments. *, P < 0.01, scFvNLDC-145-HER2 compared with other groups.