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BioMed Research International
Volume 2013 (2013), Article ID 976383, 8 pages
http://dx.doi.org/10.1155/2013/976383
Research Article

Characterization of CD8+ T-Cell Responses in the Peripheral Blood and Skin Injection Sites of Melanoma Patients Treated with mRNA Electroporated Autologous Dendritic Cells (TriMixDC-MEL)

1Laboratory of Molecular and Cellular Therapy, Department of Immunology-Physiology and Dendritic Cell Bank, Vrije Universiteit Brussel, 1090 Brussels, Belgium
2Department of Medical Oncology, Universitair Ziekenhuis Brussel, 1090 Brussels, Belgium

Received 4 June 2012; Accepted 21 July 2012

Academic Editor: Julie Curtsinger

Copyright © 2013 Daphné Benteyn et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Treatment of melanoma patients with mRNA electroporated dendritic cells (TriMixDC-MEL) stimulates T-cell responses against the presented tumor-associated antigens (TAAs). In the current clinical trials, melanoma patients with systemic metastases are treated, requiring priming and/or expansion of preexisting TAA-specific T cells that are able to migrate to both the skin and internal organs. We monitored the presence of TAA-specific CD8+ T cells infiltrating the skin at sites of intradermal TriMixDC-MEL injection (SKILs) and within the circulation of melanoma patients treated in two clinical trials. In 10 out of fourteen (71%) patients screened, CD8+ T cells recognizing any of the four TAA presented by TriMixDC-MEL cellular vaccine were found in both compartments. In total, 30 TAA-specific T-cell responses were detected among the SKILs and 29 among peripheral blood T cells, of which 24 in common. A detailed characterization of the antigen specificity of CD8+ T-cell populations in four patients indicates that the majority of the epitopes detected were only recognized by CD8+ T cells derived from either skin biopsies or peripheral blood, indicating that some compartmentalization occurs after TriMix-DC therapy. To conclude, functional TAA-specific CD8+ T cells distribute both to the skin and peripheral blood of patients after TriMixDC-MEL therapy.