Example 2
A CD26-negative malignant mesothelioma cell line MSTO-211H (MSTO) (American Type Cell Culture Collection, Manassas, Va.) was transfected with CD26 gene, which was designated as MSTO clone 12 (Aoe K et al., Clin Cancer Res. (2012) 18: 1447-56). A CD26-negative T-cell leukemia cell line Jurkat (American Type Cell Culture Collection, Manassas, Va.) was transfected with CD26 gene, which was designated as Jurkat CD26(+) (Tanaka T et al., Proc Natl Acad Sci USA (1993) 90: 4586-90). A CD26-positive cell line JMN established from malignant mesothelioma was kindly provided by professor Chikao Morimoto, the Institute of Medical Science, the University of Tokyo. All the cell lines were cultured in RPMI medium (catalog No. 11875-093, Life Technologies Corp., Carlsbad, Calif.) containing 10% heat-inactivated fetal bovine serum (FBS, Life Technologies Corp., Carlsbad, Calif.), ABPC (100 μg/ml), and streptomycin (100 μg/ml) at 37° C. under 5% CO2 environment.