Influence of immunized sera on the in vitro proliferation of SK-BR-3 cells. Diluted sera from ECD/Her2-immunized mice were able to reduce the proliferation rate by 13% (p < 0.05). SK-BR-3 cells were incubated with complement inactivated pooled immune sera obtained from vaccinated mice one day prior to cell inoculation. Immune sera were diluted 1:100. Columns and error bars represent the means and the range of values obtained from 3 independent experiments. Positive control: Herceptin.