Table 2

Abrogation of the antimetastatic effects of B7.2-IgG/TC immunization by depletion of CD4+ or CD8+ T lymphocytes

BALB/c mice were inoculated s.c. with 1 × 105 4T1 breast tumor cells. On day 4 mice received i.p. injections of anti-CD4 or anti-CD8 mAb. Injections of these mAbs were repeated twice a week. Control group of mice received 200 μg of rat IgG. On day 7, when tumors reach ∼0.5 cm in diameter, normal or CD4-, CD8-depleted mice were immunized with B7.2-IgG/TC. Immunizations were repeated on days 14 and 21. When some mice start to die the surviving mice were killed, their lungs were harvested, and metastases were counted under dissecting microscope.

MiceTreatmentNo. of miceMedian (range) of metastases
CD4+/CD8+None823 (11–63)
CD4+/CD8+B7.2-IgG/TC74 (0–37)a
CD4/CD8+B7.2-IgG/TC745 (18–84)b
CD4+/CD8B7.2-IgG/TC4c12 (2–24)b
  • a Significantly (P < 0.05) differs from all other groups according to Mann-Whitney test.

  • b Differences between these groups and control group are not significant (P > 0.05).

  • c Group contained 7 mice but 3 mice died before lungs were harvested.