Table I.

αCD70 blocks IFN-γ secretion by LACK transgenic cells primed by DEC⁺ DCs, but not by DEC⁻ DCs

			Form of LACK antigen to load DCs
DC Subset	Cytokine pg/ml	Blocking mAb	αDEC-LACK	33D1-LACK	Ig-LACK	LACK	None	LACKpep 0.02 μM
DEC+ DCs	IFN-γ	IgG2b	2,048	20	−66	463	4	2,189
		αCD70	51	34	16	−76	−61	23
	IL-4	IgG2b	−41	−89	−92	−77	−90	−30
		αCD70	−29	−71	−89	−70	−93	−79
DEC− DCs	IFN-γ	IgG2b	13	−71	25	−76	−44	80
		αCD70	15	19	23	11	−60	25
	IL-4	IgG2b	−54	471	−64	406	−96	485
		αCD70	−43	498	−70	646	−79	602

BALB/c mice (five mice per condition) were immunized for 10–12 h with 10 μg αDEC-LACK, 10 μg 33D1-LACK, 10 μg Ig-LACK, and 30 μg LACK protein in the presence of αCD40 and poly IC, or PBS. Spleens were harvested and teased in the presence of collagenase, and splenocytes were enriched for CD11c⁺ cells through MACS⁺ selection, labeled for CD11c, B220, CD3, and DEC205, and sorted. CD11c⁺ B220⁻ CD3⁻ DEC⁺/DEC⁻ subsets were collected and cultured with thy-1.1⁺ CFSE-labeled LACK TCR transgenic cells at a 1:5 ratio. αCD70 or nonreactive isotype mAb (3 μg/ml) was added to the cultures of DEC⁺ and DEC⁻ DCs with LACK TCR transgenic cells at day 1 of co-culture. After 3.5 d, T cell priming was assessed by IL-4 and IFN-γ secretion. Representative of two individual experiments.