Figure 3.

Anti-EGFR Ab induced a tumor-specific CTL response, which is required for the therapeutic effect. (a) Wild type (Wt) BALB/c mice (n = 5/group) were injected subcutaneously with 5 × 10⁵ TUBO-EGFR and treated with 200 µg of Cetuximab on days 14, 21, and 28. A CD8-depleting antibody (200 µg/mouse) was administered on the same day as Cetuximab. The tumor growth was measured and compared twice a week. *P < 0.05, compared to Cetuximab-treated Wt mice. One of three representative experiments is shown. (b) TUBO-EGFR-HA–bearing Wt mice received an adoptive transfer of 6 × 10⁶ carboxyfluorescein diacetate succinimidyl ester (CFSE)-labeled clone 4 (CL4) T cells on day 10 after tumor inoculation. Six hours later, mice were treated with 500 µg of Cetuximab or control human immunoglobulin G (IgG). Draining lymph node (LN) cells were collected 3 days later and analyzed for CFSE dilution. Data is gated on the Thy1.1⁺CD8⁺Vβ8⁺ population. *P < 0.05 compared to control group. One of two similar experiments is represented. (c) TUBO-EGFR-HA–bearing Wt BALB/c mice received an adoptive transfer of 2 × 10³ CL4 splenocytes on day 10 after tumor inoculation. Six hours later, mice were treated with 500 µg of Cetuximab or control human IgG. Draining LN cells were collected 9 days later and stimulated with hemagglutinin (HA) peptide in an interferon-γ (IFNγ) enzyme-linked immunosorbent spot (ELISPOT) assay. *P < 0.05 compared with control group. One representative experiment of three is depicted.