Table 1

Efficacy of Cγ1- or Cγ4-based Hu14.18-IL-2 immunocytokines in a xenograft model of human melanoma pulmonary metastases

Treatment groupaMetastatic scorebLung weights (g)
IgG1IgG4IgG1IgG4
PBS4, 4, 4, 40.38 ± 0.061
Hu14.18 (16 μg) + IL-24, 4, 4, 34, 4, 4, *0.27 ± 0.0610.29 ± 0.089
Hu14.18-IL2 (16 μg)0, 0, 0, 00, 0, 0, 00.17 ± 0.0080.18 ± 0.002
Hu14.18-IL2 (8 μg)3, 2, 2, 12, 2, 2, 10.20 ± 0.0410.19 ± 0.015
Hu14.18-IL2 (2 μg)4, 4, 4, 24, 4, 4, 40.26 ± 0.040.27 ± 0.041
  • a SCID mice with established pulmonary metastases, 3 days after i.v. injection with 1 × 106 M24 human melanoma cells, were injected i.p. with 1 × 107 LAK cells followed 3 h later by the first of seven daily injections of the indicated amounts of Ab, immunocytokine, and IL-2 (48,000 IU per day). On day 28 after tumor implantation, all mice were sacrificed and assessed for tumor outgrowth by metastatic scoring and by measuring lung weights.

  • b The scoring is based on the percentage surface coverage: 1, 1–25% coverage; 2, 26–50% coverage; 3, 51–75% coverage; and 4, 76–100% coverage. *, animal that died before the end of the experiment. Differences between the 8- and 16-μg dose groups of both immunocytokines were significant (P < 0.05) compared to both the PBS and Ab plus IL-2 control groups.