Figure 1.

Immune cell depletion during treatment and rechallenge. (A) Mice were depleted of CD4⁺, CD8⁺, or NK1.1⁺ lymphocytes prior to implantation of 75,000 MB49 cells in the bladder and throughout twice-weekly application of intravesical CS/IL-12 immunotherapy (arrows) begun 7 d post-implantation. Mice were monitored for hematuria and survival. All CS/IL-12 treated groups, regardless of depletion status, significantly (p < 0.05) prolonged survival over PBS treated mice. (B) Mice which had previously eradicated their tumors were depleted of CD4⁺, CD8⁺, or NK1.1⁺ lymphocytes prior to subcutaneous rechallenge with 300,000 MB49 cells. Onset of tumor growth was monitored and measured. With the exception of the CD4⁺ depleted group all curves were significantly different (p < 0.05) than naive mice. Asterisks indicate differences between groups determined via the log-rank test: *p < 0.05 or ***p < 0.0005.