Xenograft tumors and in vivo antibody treatment

SCID (C.B-17/Icr-Prkdc^skid/IcrIcoCrl, Fox-Chase) mice were purchased from Charles River Laboratories, and housed in a specific-pathogen-free environment. All animal experiments were performed in accordance with FELASA guidelines and recommendations and DIN EN ISO 9001 standards. Only non-leaky SCID mice with murine IgG levels below 100 ng/ml were used. Each seven-week-old female SCID mouse participating in the study was given a subcutaneous injection of 5 × 10⁶ JIMT-1 cells suspended in 100 µl Hanks' A buffer and mixed with an equal volume of Matrigel (BD Matrigel, BD Biosciences, 356237) in both flanks. Tumor volumes were derived as the product of the length, width and height of the tumor measured 2 times a week with a caliper. Trastuzumab (n = 8), trastuzumab F(ab’)₂ (n = 7), pertuzumab (n = 8), pertuzumab F(ab’)₂ (n = 7), trastuzumab+pertuzumab (n = 8), trastuzumab F(ab’)₂ + pertuzumab F(ab’)₂ (n = 7), and, as a control, HEPES buffer (n = 7) was injected intraperitoneally in a volume of 100 µl HEPES buffer twice weekly. The injected dose was 100 µg of each antibody or F(ab’)₂ used. Treatment commenced at the time of JIMT-1 inoculation and was continued until the end of the experiment. At the end of the experiment the animals were euthanized by cervical dislocation. The experiments were done with the approval of the National Ethical Committee for Animal Research (# 4/2012/DE MÁB).