Anti-Interleukin-10R1 Monoclonal Antibody Enhances Bacillus Calmette-Guerin Induced T-Helper Type 1 Immune Responses and Antitumor Immunity in a Mouse Orthotopic Model of Bladder Cancer

Purpose: Properinduction of the T-helper type 1 immune response is required for effective bacillus Calmette-Guerin immunotherapy for bladder cancer. Interleukin-10 down-regulates the T-helper 1 response and is associated with bacillus Calmette-Guerin failure. We investigated whether blocking interleukin-10 receptor 1 would enhance the bacillus Calmette-Guerin induced T-helper type 1 immune response and anti-bladder cancer immunity in a mouse model. Materials and Methods: Splenocytes were incubated with bacillus Calmette-Guerin or bacillus Calmette-Guerin plus control IgG1, anti-interleukin-10 receptor 1 mAb or anti-interleukin-10 neutralizing mAb, followed by enzyme-linked immunosorbent assay of interferon-gamma production. Bladder RNA was extracted after intravesical bacillus Calmette-Guerin plus intraperitoneal IgG1 or anti-interleukin-10 receptor 1 mAb and analyzed by reverse transcriptase and/or quantitative polymerase chain reaction. Urine was collected and analyzed by enzyme-linked immunosorbent assay. Mice bearing a luciferase expressing MB49 orthotopic tumor were treated with intravesical bacillus Calmette-Guerin plus intraperitoneal IgG1 or anti-interleukin-10 receptor 1 mAb. Tumor response was assessed by bioluminescent imaging and bladder weight measurement. Results: Bacillus Calmette-Guerin plus anti-interleukin-10R1 mAb induced significantly higher interferon-gamma production by splenocytes than bacillus Calmette-Guerin plus anti-interleukin-10 mAb. Bacillus Calmette-Guerin plus anti-interleukin-10 receptor 1 mAb also induced significantly higher interferon-gamma mRNA and protein in bladder and urine, respectively, in a dose dependent manner. Treatment with phosphate buffered saline, bacillus Calmette-Guerin plus control IgG1 and bacillus Calmette-Guerin plus anti-interleukin-10 receptor 1 mAb showed a 0% tumor-free rate with a 20% death rate, a 20% tumor-free rate with a 20% death rate and a 40% tumor-free rate with a 0% death rate, respectively. Bladder weight also revealed the effect of anti-interleukin-10 receptor 1 mAb on the bacillus Calmette-Guerin induced bladder tumor response. Conclusions: Anti-interleukin-10 receptor 1 mAb enhanced the bacillus Calmette-Guerin induced T-helper type 1 immune response and anti-bladder cancer immunity. A humanized form of this mAb warrants future investigation for bacillus Calmette-Guerin treatment of bladder cancer.