Table I.

CD4 depletion induces immune responses against antigens other than Ld

First tumor challengeaRechallengea
GroupTumor lineDoseTreatmentTumor lineDoseIncidence of tumor growthbPercent
1Ag104Ld5 × 105Surgical removalcAg104Ld1060/30
25 × 105Ag1041063/3100
35 × 105CD4 depletiondAg104Ld1060/100
45 × 105Ag1041060/70
5NoneNoneAg104Ld10633/33100
6Ag10410620/20100
  • a Number of tumor cells as indicated were injected s.c. to C3B6F1 mice. Rechallenge was done 30 d after first tumor was surgically removed or rejected upon anti-CD4 antibody treatment.

  • b The results were pooled from independent experiments. p-values calculated by chi-square test between groups were shown as follows: P < 0.001 for group 1 versus group 5, group 3 versus group 6, and group 4 versus group 6. P > 0.5 for group 2 versus group 5.

  • c The tumors were surgically removed 21 d after first tumor challenge.

  • d CD4+ cells were depleted by anti-CD4 antibody 14 d after first tumor challenge. Depletion was confirmed by checking peripheral blood with FACS.