Figure 1.
Reversal of unresponsiveness to MUC1 antigen in MUC1 transgenic mice immunized with FC/MUC1. (A) MUC1.Tg mice were immunized twice (7-day interval) with PBS or 5 × 105 FC/MUC1 cells. The mice (10 per group) were challenged with 1 × 106 MC-38 cells, 1 × 106 MC-38/MUC1 cells, 5 × 105 MB49 bladder carcinoma, or 5 × 105 MB49/MUC1 cells. Tumors >3 mm in diameter were scored as positive. Similar results were obtained in three separate experiments. (B) MUC1.Tg mice were immunized twice (7-day interval) with 5 × 105 FC/MUC1 cells. After 20 days, splenocytes were isolated and incubated at the indicated effector:target ratios with 51Cr-labeled MC-38 (○), MC-38/MUC1 (•), MB49 □, and MB49/MUC1 (▪) target cells. CTL activity was determined by 51Cr release. (C) MUC1.Tg mice were immunized twice with 5 × 105 FC/MUC1 (•), irradiated MC38/MUC1 (▪), or PBS (□). Serum samples were collected at 14 days after the last immunization and analyzed for the presence of antibodies to MUC1 by an enzyme-linked immunoabsorbent assay.