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Intravesical administration of Mycobacterium bovis bacillus Calmette-Guérin (BCG) continues to be a successful immunotherapy for superficial bladder cancer. Recently, our laboratory observed the expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo-2L) on neutrophils in voided urine following BCG therapy. Neutrophils release a soluble and functional form of TRAIL when stimulated in vitro with BCG and the activity was localized predominantly to the cell wall fraction. In this study, we examined the ability of individual mycobacterial subcomponents to stimulate TRAIL release from neutrophils. Our results demonstrate that cell wall derived LAM, mAGP, and the Tx114 soluble protein pool were effective agonists of TRAIL release from neutrophils. Mycobacterial DNA was also an agonist of TRAIL release from neutrophils. Furthermore, the purified Antigen 85 ABC complex and alpha-crystallin (hspX), two major cell wall antigens present in the Tx114 pool, induced TRAIL release from neutrophils. The Tx114 pool stimulated HEK-293 cells expressing either TLR2/1 or TLR2/6, but only hspX was able to stimulate TLR2/6 expressing cells. HEK293-TLR4/MD2/CD14 cells responded only to LAM. Collectively, these results suggest TRAIL release from neutrophils was induced through the recognition of multiple mycobacterial components by TLR2 and TLR4.

98th AACR Annual Meeting-- Apr 14-18, 2007; Los Angeles, CA