Intranodal injection of semimature monocyte-derived dendritic cells induces T helper type 1 responses to protein neoantigen.

Dendritic cells (DCs) represent the most potent antigen-presenting cells of the immune system capable of initiating primary immune responses to neoantigens. Here we characterize the primary CD4 T-cell immune response to protein keyhole limpet hemocyanin (KLH) in 5 metastatic melanoma patients undergoing a tumor peptide-based dendritic cell vaccination trial. Monocyte-derived dendritic cells displaying a semimature phenotype, as defined by surface markers, were loaded ex vivo with antigen and injected intranodally at weekly intervals for 4 weeks. All patients developed a strong and long-lasting delayed-type hypersensitivity reactivity to KLH, which correlated with the induction of KLH-dependent proliferation of CD4 T cells in vitro. Secondary in vitro stimulation with KLH showed significant increase in interferon-gamma and interleukin-2 (IL-2) but not IL-4, IL-5, nor IL-10 secretion by bulk T cells. On the single-cell level, most TH1 cells among in vitro-generated KLH-specific T-cell lines confirmed the preferential induction of a KLH-specific type 1 T helper immune response. Furthermore, the induction of KLH-specific antibodies of the IgG2 subtype may reflect the induction of a type 1 cytokine profile in vivo after vaccination. Our results indicate that intranodal vaccination with semimature DCs can prime strong, long-lasting CD4 T-cell responses with a TH1-type cytokine profile in cancer patients.

Functional expression of the eotaxin receptor CCR3 in CD30+ cutaneous T-cell lymphoma.

Little is known about mechanisms involved in skin-specific homing of cutaneous T-cell lymphoma (CTCL). Chemokine/chemokine receptor interactions have been implicated in the homing of lymphoma cells to various tissue sites. We investigated tissue samples and tumor cell suspensions of patients with CD30(+) CTCL (n = 8) and CD30(-) CTCL (mycosis fungoides, n = 6; Sézary syndrome, n = 6) for expression of the chemokine receptors CCR3, CCR4, and CCR8 and the CCR3 ligands eotaxin/CCL11, monocyte chemoattractant protein 3 (MCP-3)/CCL7, and RANTES (regulated on activation, normal T expressed and secreted)/CCL5. Of 8 CD30(+) CTCLs, 7 expressed CCR3, 4 CCR4, and none CCR8. CCR3 expression was not found in skin tissue samples from 12 CD30(-) CTCLs. Coexpression of CCR3 and CD30 was demonstrated by flow cytometry in tumor cell suspensions. Internalization experiments demonstrated functionality of CCR3 expressed by freshly isolated tumor cells. Actin polymerization as well as migration in response to eotaxin was demonstrated in a CD30(+) cutaneous lymphoma cell line. CCR3 ligand eotaxin/CCL11 was detected in lesional skin of CD30(+) CTCL by immunohistochemistry, preferentially in tumor cells. Eotaxin/CCL11 expression in tumor cells was confirmed by intracellular immunofluorescence. Analysis of cytokine expression pattern of CCR3-bearing infiltrating cells showed a predominance of interleukin-4 (IL-4) but not interferon-gamma (IFN-gamma) protein expression,1 consistent with a T-helper 2 (Th-2) profile. These results suggest that expression of CCR3 and its ligand eotaxin/CCL11 plays a role in the recruitment and retention of CD30(+) malignant T cells to the skin.