Expression of chemokine/cytokine genes and immune cell recruitment following the instillation of Mycobacterium bovis, bacillus Calmette-Guérin or Lactobacillus rhamnosus strain GG in the healthy murine bladder.

Mycobacterium bovis, bacillus Calmette-Guérin (BCG) is the current gold standard for bladder cancer therapy. In this study a profile of the gene expression changes that occur after BCG instillation in the bladders of healthy mice was produced and compared to the type of immune cells recruited into the bladder. A similar comparison was made for Lactobacillus rhamnosus strain GG (LGG) instillations in healthy mice to determine its potential in the immunotherapy of bladder cancer. Mice were given six weekly instillations and were killed after the fourth, fifth and sixth instillations of BCG or LGG. Their bladders were harvested for chemokine/cytokine messenger RNA analysis using an array as well as semi-quantitative reverse transcription-polymerase chain reaction. In a second set of mice both the bladder and draining lymph nodes were harvested for the analysis of immune cells. BCG significantly upregulated genes for T helper type 1 (Th1) chemokines: Cxcl2, Cxcl9, Cxcl10, Xcl1; and increased the expression of Th1/Th2 chemokines: RANTES, Ccl6 and Ccl7; Th1 polarizing cytokines: Il1beta and Tnfa; and Fcgammar1 and iNOS as early as after four weekly instillations. Most of these genes remained highly expressed after 6 weeks. In contrast, LGG transiently induced Cxcl10, Il16, Fcepsilonr1 and Il1r2. Despite these findings, LGG instillation induced the recruitment of natural killer cells into the bladder and draining lymph nodes, as was observed for BCG instillation.