Table II.

Augmented rejection of tumor through elimination of CD4⁺ cells

	Tumor challengea
Group	Tumor line	Dose	Treatment	Incidence of tumor growthb	Percent
1	Ag104Ld	106	None	33/33	100
2		105		27/27	100
3		106	CD4 depletionc	0/9	0
4		105		0/13	0
5		105	CD4 and CD8 depletiond	6/6	100
6		106	NK depletione	3/3	100
7		105	NK and NKT depletionf	6/6	100
8	Ag104	105	None	15/15	100
9		105	CD4 depletionc	4/8	50

^aNumber of tumor cells as indicated were injected s.c. to C3B6F1 mice.

^bThe 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 3, group 2 versus group 4, and group 4 versus group 5, P = 0.0015 for group 8 versus group 9.

^cCD4⁺ cells were depleted by anti-CD4 antibody 3 d before and 10 d after tumor challenge.

^dCD4⁺ cells were depleted by anti-CD4 antibody 3 d before and 10 d after tumor challenge. CD8⁺ cells were depleted by anti-CD8 antibody 14 d after tumor challenge.

^eNK cells were depleted by antiasialo GM-1 antibody 3 d before tumor challenge.

^fNK and NKT cells were depleted by anti-NK1.1 antibody 3 d before and 10 d after tumor challenge. Depletion of various cell populations was confirmed by checking peripheral blood by FACS.