Specificity of antibodies against native Her2/neu. Antibodies from sera of ECD/Her2-immunised mice are specific against the human Her2/neu molecule, as seen with immunoprecipitation assay. Her2/neu protein extracted from SKBR- cells immunoprecipitated with antibodies from immunized sera and then subjected to immunoblotting using C18 anti-Her2/neu antibody. Sera ECD mice: Sera from ECD/Her2 vaccinated mice. Sera PBS mice: Sera from PBS vaccinated mice (control group). Positive control: Herceptin. Negative control: PBS. SK-BR-3 lysate: SK-BR-3 cell lysate was used for detection of Her2/neu molecular weight.