Table 1.

The phenotype of the cells mediating tumor elimination

Type of injected cells*	Mice developing tumors
	Exp. 1	Exp. 2
T alone	4/4–100%†	6/6–100%
T + Norm Ad	4/4–100%	8/8–100%
T + Norm non-Ad	4/4–100%	8/8–100%
T + Reg Ad	4/4–100%	7/7–100%
T + Reg non-Ad	0/4–0%	1/6–17%
T + Reg non-Ad + CD8+ C′	n.d.	4/6–67%
T + Reg non-Ad + CD4+ C′	n.d.	1/6–17%

^*MOPC-315 tumor cells (T; n = 10⁴) were mixed with spleen lymphoid cells at a ratio of 1∶250 and immediately injected s.c. (0.1 ml) into BALB/c mice. Spleen cells from regressors (Reg) and normal (Norm) age-matched controls were separated on nylon–wool columns to adherent (Ad) and nonadherent (non-Ad) subpopulations. Part of the Reg non-Ad purified T cells were treated further with either anti-CD4 or anti-CD8 mAbs plus rabbit complement (C′). Spleen cells were taken from Epo-induced regressors 2.5 months in regression (Exp. 1) or 5.5 months in regression (Exp. 2). 

^† Number of mice with tumors 25 days after MOPC-315 transplantation.