Fig 3.

(A) Antipeptide antibodies recognize human epidermal growth factor receptor 2 (HER2). Flow cytometry was used to assess the binding capabilities of the antipeptide antibodies of patients (4A through 4F) to HER2. Purified antibodies (50 μg) from presera and immunized sera were tested against BT-474 breast cancer cells. Histograms contain overlays of antipresera postsera (3y + 4w) and trastuzumab. (B) Purified antipeptide antibodies cause antibody-dependent cellular cytotoxicity. BT474 target cells were incubated with different amounts of effector cells (ie, peripheral-blood mononuclear cells) after adding 100 μg of antipeptide antibodies for patients 4A through 4F. Trastuzumab was used as the positive control, and normal human and mouse immunoglobulin G (IgG) were used as negative controls. The percentage cytotoxicity was calculated according to instructions provided by the reagent kit.