Inhibition of B7-1 expressing RMA-S tumor growth in Lass5-antigen immunized mice.

<p>A: a) B7-1 expression in the transfectants. B7-1 expression was determined by FACS assay using FITC-conjugated anti-mouse CD80 mAb; b, c and d) NK1.1 population in mouse splenocytes were detected by anti-NK1.1 mAb. b) Normal mouse splenocytes, c) and d) the splenocytes from tumor-immunized and anti-NK1.1 mAb treated mouse (c: on the tumor cell challenge time and d: end of experiment). B and C: <i>In vivo</i> tumor growth assays. B: e) mice immunized with PBS (0), Lass5-peptide-pulsed and mitomycin-c-treated RMA-S/pUB (1) or RMA-S/B7-1 (2) cells. After immunization, the mice were challenged s.c with RMA-S/pUB or RMA-S/B7-1 cells. The insert indicates tumor growth during the time point of the initial tumor cell injection through two weeks. f) Mice immunized with Lass5-peptide-pulsed and mitomycin-c-treated RMA-S/pUB cells and followed by anti-NK1.1 mAb treatment. Afterwards, the mice were challenged s.c with RMA-S/pUB or RMA-S/B7-1 cells. Statistical analysis of tumor sizes indicated significant differences between RMA-S/pUB ‘’ and RMA-S/B7-1 ‘*’ cell challenge groups at relevant time points (P value≤0.05 or 0.01). C: Tumor sizes at the endpoint were shown in the mice immunized with Lass5-peptide-pulsed and mitomycin-c-treated RMA-S/pUB or RMA-S/B7-1 cells and followed by challenge with live RMA-S/pUB or RMA-S/B7-1 cells.