Development of Immunogenic Tumor-Loaded Dendritic Cells Through Physical Perturbation and Apoptotic Cell Loading

Abstract

To improve understanding of the forces that drive monocytes to transition into dendritic cells (), we developed an experimental system that converts monocytes to DC by passage of leukocytes through a 400 μm silica bead column. The results demonstrate that overnight culture of column-treated monocytes causes a phenotypic conversion that is characteristically displayed by immature DC. These phenotypic changes were enhanced when the DC were loaded with apoptotic cells, leading to increased expression of the DC maturation-associated markers CD83, CD80 and the chemokine receptor CCR7. The DC demonstrated potent induction of allogeneic T cell proliferation and the capacity to activate autologous CD8⁺ T cells. The CD8 T cells expressed augmented levels of perforin, IFN-γ and TNF-α and mediated CTCL cell apoptosis. These studies demonstrate that physical contact with silica beads combined with loading of apoptotic tumor cells induces synchronized, rapid conversion of human monocytes to DC, which can efficiently stimulate CD8⁺ T cells. These results may aid in the development of more efficient DC vaccines that can be loaded with the universe of antigens available in apoptotic tumor cells in a rapid, clinically practical fashion.

Keywords:

• Dendritic cells
• Cutaneous T cell lymphoma
• Immunotherapy

ABBREVIATIONS
CPM:	=	counts per minute
CTCL:	=	cutaneous T cell lymphoma
DC:	=	dendritic cells
ECP:	=	extracorporeal photochemotherapy
8-MOP:	=	8-methoxypsoralen
MFI:	=	mean fluorescent intensity
MLC:	=	mixed leukocyte culture
MNL:	=	mononuclear leukocytes
TI:	=	Transimmunization