Table 1.

Failure to abrogate tolerance to MC-C tumor in tolerant mice joined in parabiosis with immune mice

Parabiotic miceb	Tumor takes of challenge implant of MC-C/totala
	Tolerant	Immune	Normal
Tolerant × immune	6/6	6/6*
Immune × normal		0/4*	0/4**
Normal × normal			9/9**

^aNumber of mice in which tumor challenge grew/total number of mice inoculated. Tumor challenge was 2 × 10⁵ MC-C tumor cells implanted in the dorsum of both partners of parabiotic mice, 9 days after parabiosis

^bParabiotoc mice: tolerant mice were mice bearing MC-C tumors growing s.c. in the opposite flank to the parabiotic junction and larger than 500 mm³ at the time when parabiosis was carried out. Immune mice were mice pretreated with lethally X-irradiated MC-C tumor cells, 14 and 7 days before parabiosis. Single tolerant and single normal mice failed to reject an implant of 2 × 10⁵ MC-C tumor cells in five of the five and nine of the nine cases, respectively. Single immune mice rejected that tumor implant in six of the six cases

^*  P < 0.05 (6/6 vs 0/4); ^**  P < 0.01 (0/4 vs 9/9)