Dynamics of antigen delivery and the functional roles of L121-adjuvant.

Abstract This study investigates the intracellular transport of protein antigens facilitated by L121-adjuvants and examines the associated cytotoxic T lymphocyte (CTL) effect. EL4 mouse thymoma cells were treated with L121-adjuvant and stained with AnnexinV-propidium iodide (PI) followed by flow cytometric analysis. The intracellular trafficking dynamics of bovine serum albumin (BSA)-FITC in the J774.A.1 macrophages, influenced by the L121-adjuvant, was visualized by confocal microscopy. The antigen-specific cytotoxic T lymphocyte (CTL) effect induced by the L121-adjuvant was determined by the cleavage-specific fluorogenic caspase substrate. The trafficking of BSA-FITC in the J774A.1 cells by confocal microscopy illustrated that the L121-adjuvant facilitated the intracellular transport of proteins to the subcellular compartments, including the lysosome, endoplasmic reticulum (ER), and the cis -Golgi apparatus. The L121-adjuvant also facilitated antigen delivery to the dendritic cells in the lymph nodes. Immunization of mice with the L121-adjuvant resulted in cell-mediated cytotoxic responses in the target cells, as detected by PhiPhiLux, a fluorogenic caspase substrate. Taken together, the L121-adjuvant improved the dynamics of protein delivery to antigen presenting cells, and also induced caspase activation, thereby illustrating the mechanism of antigen-specific CTL effects.