Tumour-loaded α-type 1-polarized Dendritic Cells from Patients with Chronic Lymphocytic Leukaemia Produce a Superior NK-, NKT- and CD8+ T Cell-attracting Chemokine Profile

Tumour-loaded dendritic cells (DCs) from patients with chronic lymphocytic leukaemia (CLL) matured using an a-type 1-polarized DC cocktail (IL-1 beta/TNF-alpha/IFN-alpha/IFN-gamma/poly-I:C;alpha DC1) were recently shown to induce more functional CD8(+) T cells against autologous tumour cells in vitro than DCs matured with the 'standard' cocktail (IL-1 beta/TNF-alpha/IL-6/PGE(2);PGE(2)DCs). However, the ability of vaccine DCs to induce a type 1-polarized immune response in vivo probably relies on additional features, including their ability to induce a CXCR3-dependent recruitment of NK cells into vaccine-draining lymph nodes. Moreover, their guiding of rare tumour-specific CD8(+) T cells to sites of DC-CD4(+) T cell interactions by secretion of CCL3 and CCL4 is needed. We therefore analysed the chemokine profile and the lymphocyte-attracting ability in vitro of monocyte-derived PGE(2)DCs and alpha DC1s from patients with CLL. alpha DC1s produced much higher levels of CXCR3 ligands (CXCL9/CXCL10/CXCL11) than PGE(2)DCs. Functional studies further demonstrated that alpha DC1s were superior recruiters of both NK and NKT cells. Moreover, alpha DC1s produced higher levels of CCL3/CCL4 upon CD40 ligation. These findings suggest that functional alpha DC1s, derived from patients with CLL, produce a desirable NK-, NKT- and CD8(+) T cell-attracting chemokine profile which may favour a guided and Th1-deviated priming of CD8(+) T cells, supporting the idea that alpha DC1-based vaccines have a higher immunotherapeutic potential than PGE(2)DCs.