Effects of anti-Ly6G antibodies on colon carcinogenesis.

<p>(<b>A</b>) Schematic overview of anti-Ly6G antibody administration. Colons were removed on day 67 after the mice were administered anti-Ly6G antibodies or a vehicle control from day 56 to day 62. (<b>B</b>) Colons were removed on day 67 from the mice treated with anti-Ly6G antibodies or a vehicle control, and tumors were evaluated macroscopically. Representative results of 5 mice are shown. (<b>C</b>) The numbers of macroscopic tumors in the colons removed on day 67 were determined. Each value represents mean ± SD (n = 5 mice/group). **p<0.01 versus mice treated with the vehicle control. (<b>D</b>) Colons were processed for H&E staining, and representative results of 5 mice are shown. Original magnification, 200×. (<b>E</b>) Ly6G⁺ neutrophils were counted as described in the Materials and Methods. Values represent mean ± SD of the number of Ly6G⁺ neutrophils per field from 5 mice. *p<0.05, **p<0.01 versus control mice or mice treated with the vehicle control. (<b>F</b>–<b>H</b>) Quantitative RT-PCR analyses for <i>CXCR2</i> (<b>F</b>), <i>CXCL2</i>(<b>G</b>), and <i>CXCL5</i> (<b>H</b>) were performed on total RNA extracted from colons at the indicated times as described in the Materials and Methods. <i>CXCR2</i>, <i>CXCL2</i>, and <i>CXCL5</i> mRNA levels were normalized with <i>GAPDH</i> mRNA levels. *p<0.05, **p<0.01 versus mice treated with the vehicle control. (<b>I</b> and <b>J</b>) CXCR2⁺ (<b>I</b>) and CXCL2⁺ (<b>J</b>) cells were detected by immunohistochemical analyses of mouse colon tissues. The colons were removed on day 67 from the mice treated with anti-Ly6G antibodies or a vehicle control. Analysis was performed using anti-CXCR2 or anti-CXCL2 antibodies as described in the Materials and Methods. The numbers of cells per field were counted in 5 randomly selected visual fields at 400× magnification. Values are mean ± SD for 5 mice in each group. *p<0.05, **p<0.01 versus control mice or mice treated with the vehicle control.