Cellular attachment and internalization of cationic liposomes containing mycobacterial cell wall

[[abstract]]The cell wall derived from Mycobacterium bovis bacillus Calmette-Gue?rin (BCG) is apotent immunopotentiator and has recently been suggested as an alternative treatment for in situ bladder carcinoma. In contrast to the live BCG, the loss of infectivity and the negatively charged nature of BCG cell wall physically inhibit its attachment and subsequent internalization to the urothelial bladder cells. As part of our research involving the delivery of macromolecules to target cells, we developed cationic liposomes that anchor arginine octamers on the liposome surface. In this study, we used cationic liposomes as a delivery tool to facilitate the attachment and internalization of the BCG cell wall. Using confocal scanning microscopy, we verified that cationic liposomes incorporated with BCG cell wall could attach to the cellular membrane of murine bladder tumour (MBT-2) cells and become internalized. Cationic liposomes containing BCG cell wall were taken up by MBT-2 cells mainly via clathrin-mediated endocytosis. These results would be useful to understand the mechanism of action of BCG cell wall against bladder tumour cells as well as to develop an immunotherapeutic agent for clinical use