Table 1

The Role of iNOS and NADPH Oxidase in Mediating Tumor Rejection in Response to B16-GM-CSF Vaccination

WT no vaccineNOS−/− no vaccineWT B16-GM-CSFNOS−/− B16-GM-CSF
Exp. 10/5 (0%)0/5 (0%)10/10 (100%)6/10 (60%)
Exp. 20/5 (0%)0/5 (0%) 9/10 (90%)5/10 (50%)
WT no vaccineX-CGD no vaccineWT B16-GM-CSFX-CGD B16-GM-CSF
Exp. 10/5 (0%)0/5 (0%)8/10 (80%)3/10 (30%)
Exp. 20/5 (0%)0/5 (0%)8/10 (80%)3/10 (30%)
Exp. 30/5 (0%)0/5 (0%)9/10 (90%)4/10 (40%)
  • Wild-type (WT), iNOS−/−, and X-CGD C57BL/6 mice were injected subcutaneously in the left flank with 106 irradiated (50 Gy) BI6-GM-CSF cells. Mice were challenged 2 wk later in the right flank with 105 live B16-WT cells. Results are presented as number of tumor free survivors after 8 wk over the total number of mice. P = 0.0084 by two-sided Fisher's exact test comparing vaccinated wild-type and NOS−/− mice. Fisher's exact test (rather than the χ2 test) was used to test the difference in the proportion of tumor-free survivors comparing vaccinated wild-type versus NOS−/− mice because of the small numbers of expected and observed vaccinated wild-type mice that developed tumors. The test suggests a significant difference between the proportion of tumor-free survivors in the wild-type and NOS−/− mice (P = 0.0084), with an odds ratio of 15.54 (95% confidence interval: 1.73–139.65 using Woolf's procedure). P = 0.001 by χ2 test comparing vaccinated wild-type and X-CGD mice.