Biomedical subjects

Kirsten Colling

Publications and source records attributed to Kirsten Colling.

3 recordsLinked to original sources

PubMed2003

Preparation of peptide-loaded dendritic cells for cancer immunotherapy.

Dendritic cell-based vaccines are being evaluated in clinical trials to determine their ability to activate clinically relevant tumor antigen-specific immune responses. Although some groups isolate dendritic cells from peripheral blood, most have found it more efficient to generate large numbers from peripheral blood progenitors, particularly plastic adherent or CD14+ monocytes, in media supplemented with GM-CSF and IL-4. These DC may then be matured, if desired, and loaded with antigen, such as tumor-associated peptides, prior to administration. We describe the scheme that we are currently using to generate peptide-loaded dendritic cells for our clinical trials of cancer immunotherapy.

CD40 Ligand↗

PubMed2003

HER2 dendritic cell vaccines.

HER2/neu, a tumor antigen overexpressed by a third of breast cancers, is a potential target for vaccine therapies. A particularly potent immunization strategy to induce T-cell responses against tumor antigens is to use dendritic cells (DCs) loaded with the tumor antigen. We performed two small studies to test the safety, feasibility, and immunologic and clinical responses to immunizations with in vitro-generated DCs loaded with either a human leukocyte antigen A2-restricted peptide fragment of the extracellular domain of the tumor antigen HER2 (E75) or a HER2 intracellular domain (ICD) protein in patients with high-risk resected breast cancer or metastatic cancers expressing HER2. There were no toxicities due to the immunizations in any of the patients. In the study of DCs loaded with the E75 peptide, 1 of 6 patients with metastatic HER2-expressing malignancies who completed all immunizations had stable disease for 6 months; the remainder of the patients had progressive disease. Delayed-type hypersensitivity (DTH) reactivity (2-3 mm of induration) at E75-loaded DC injection sites was observed in 2 of 5 patients evaluated but was similar at the unloaded DC injection sites. In 2 patients, the DTH sites underwent biopsy and a perivascular infiltrate of CD4 and CD8 cells was demonstrated, which was greater in the E75-loaded DC injection sites than in the unloaded DC sites. In the pilot study of ICD-loaded DC in patients with high-risk resected breast cancer, all 3 patients enrolled had no evidence of recurrence at a follow-up of up to 2.5 years. Intracellular domain-specific T-cell responses were detected directly from the peripheral blood by enzyme-linked immunospot and proliferation assay in 2 patients. We conclude that it is feasible and safe to generate and administer HER2-loaded DCs to patients with advanced HER2/neu-expressing malignancies and high-risk breast cancer. The magnitude of the immune responses generated is fairly modest, and more potent DC loading and maturation strategies will be necessary to optimize these vaccines.

Adult↗

PubMed2002

Multiple signals are required for maturation of human dendritic cells mobilized in vivo with Flt3 ligand.

The ligand for the receptor tyrosine kinase fms-like tyrosine kinase 3 (Flt3L) is a growth factor for hematopoietic progenitors and induces expansion of the two distinct lineages of dendritic cells (DC) that have been described in humans. These two lineages, DC1 and DC2, have been described according to their ability to induce naive T cell differentiation to T helper cell type 1 (Th1) and Th2 effector cells, respectively. The immunoregulatory potential of DC1 and DC2 depends on their state of maturation and activation, which can be mediated by several molecules. Because monocyte-derived DC1 produce interleukin-12 (IL-12) when stimulated with CD40 ligand (CD40L), we hypothesized that similar results would be obtained with DC1 mobilized by Flt3L. Unexpectedly, we found that immature DC expanded in vivo by Flt3L treatment could not be stimulated to produce IL-12 in vitro using CD40L and/or interferon-gamma (IFN-gamma) alone. Instead, we found that Flt3L-mobilized DC from cancer patients require a sequence of specific signals for maturation, which included initial treatment with granulocyte macrophage-colony stimulating factor followed by a combination of maturation signals such as CD40L and IFN-gamma. Flt3L-mobilized DC matured in this manner possessed greater T cell-stimulatory function than nonmatured DC. The ability to generate phenotypically mature, IL-12-producing DC1 from peripheral blood mononuclear cells mobilized by Flt3L will have important implications for the development of effective cancer immunotherapy strategies.

Antigens, CD↗