Eosinophils and neutrophils contain telomerase degradative activity. Lane 1, an extract corresponding to 50 eosinophils was mixed with the Hela cell line (0.28 μg/assay) and preincubated for 20 minutes at RT before the TRAP assay. Lanes 2 and 3, repeat experiment with 5 eosinophils or lysis mixed with the cell line. Lane 4, 50 eosinophils mixed with the Hela cell line (0.28 μg/assay) and preincubated for 40 minutes at RT before the TRAP assay. Lanes 5 and 6, repeat experiment with 5 eosinophils or lysis mixed with the cell line. Lanes 7 and 8, 50 eosinophils mixed with the Hela cell line (0.28 μg/assay) and preincubated for 150 minutes at RT before the TRAP assay with or without placental RNase inhibitor (1 U/μL) present. Lane 9, an extract corresponding to 500 neutrophils was mixed with the Hela cell line (0.14 μg/assay) and preincubated for 5 hours at RT before the TRAP assay. Lanes 10 and 11, repeat experiment with 1 U/μL and 10 U/μL placental RNase inhibitor present, respectively. Notice that the rescue of the cell line-derived telomerase activity was increased with increasing amounts of the RNase inhibitor present.