Determination of IL-13 toxin at tumor bed by Western blot analysis.

The KS Y-1 tumors injected with IL-13 toxin (250 μg/kg, IT) were excised, homogenized, and supernatant collected as described in “Materials and methods.” Aliquots of standard IL-13 toxin (lanes 2, 0.1 μg; lane 3, 0.5 μg; lane 4, 1.0 μg; lane 5, 2.0 μg), supernatants containing 40 μg total protein from control tumor (lane 6), 2 hours (lane 7), 4 hours (lane 8), and 24 hours (lane 9) after injection were run on 10 % SDS-PAGE gel. Molecular weight markers (lane 1) are shown in kilodaltons (kd) on the left. The 50 kd arrow on the right indicates the approximate size of IL-13 toxin.