Tumor-specific T cells signal tumor destruction via the lymphotoxin β receptor

Table 3 The effect of IFN-γ neutralization on adoptive immunotherapy.

Adoptive immunotherapy ^a				Mean number of pulmonary metastases ^b
Donor	Hosts	Number of T cells transferred	Blocking proteins^b	Exp.1	Exp.2
None	wt	0	none	250	250
LKO	wt	15	rat IgG	0 ^d	81(35)^d
LKO	wt	15	Anti-IFN-γ	39(29)^d	242(8)^e

a)Rag1k/o mice were reconstituted with naïve 20 × 10⁶ naïve spleen cells from naïve wt or LT-α k/o mice. They were then vaccinated s.c. with D5-G6 tumor cells, and TVDLN were harvested 8 days later. Lymph node cells were stimulated in vitro with anti-CD3 for two days and then expanded for three days in 60 IU/ml IL-2. Effector cells were harvested and 15 × 10⁶ T cells were adoptively transferred into animals with established 3-day D5 pulmonary metastases. IL-2 (90,000 IU) was administered daily i.p. for four consecutive days following adoptive transfer.
b)Purified control rat IgG or rat anti-mouse IFN-γ antibody (250 μg) was directly administered i.v. after adoptive transfer of the T cells and for the following 3 days once per day.
c) Mice were sacrificed 13 days following i.v. inoculation of tumor and the number of pulmonary metastases enumerated in a blinded fashion. Results presented are the mean and SE of 5 mice. Metastases that were too numerous to count accurately were known to be greater than 250 metastases and were assigned a value of 250.
d) p < 0.05 compared to IL-2 alone treated controls.
e) p > 0.05 compared to IL-2 alone treated controls.

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