A, Apoptotic cells in tumor sections were examined by fluorescence microscopy after DAPI and TUNEL staining as described in material and methods. The apoptotic index was determined as the number of DAPI-stained, TUNEL-positive cells that were counted. Values are the mean ± S.D. of four experimental animals. * indicates statistically significant differences from CCR5+/+ mice. Scale bar indicates 50 µm. B and C, Apoptotic protein (cleaved caspase-3 and Bax) in tumor sections were detected by immunofluorescence assay. The reactive cell number was determined as the number of DAPI-stained, Specific antibody (cleaved caspase-3 and Bax)-positive cells that were counted. Values are the mean ± S.D. of four experimental animals. * indicates statistically significant differences from CCR5+/+ mice. Scale bar indicates 50 µm. D, The expression of apoptotic proteins was detected by Western blotting using specific antibodies; cleaved caspase-3, cleaved caspase-9, cleaved PARP, Bax, Bcl-2 and c-IAP1 in the tumor tissues. The β-actin protein was used as an internal control. Each band is representative of three independent experimental results. Data are means ± S.D. of three experimental animals. * indicates significant difference from CCR5+/+ mice (p<0.05).