Document Type

Article

Publication Date

1999

Keywords

cancer vaccines, CD8-Positive T-Lymphocytes, dendritic cell, lymphocytic infiltration, lymph node metastasis, melanoma, vaccination

Abstract

Dendritic cells (DCs) are considered to be promising adjuvants for inducing immunity to cancer. We used mature, monocyte-derived DCs to elicit resistance to malignant melanoma. The DCs were pulsed with Mage-3A1 tumor peptide and a recall antigens, tetanus toxoid or tuberculin. 11 far advanced stage IV melanoma patients, who were progressive despite standard chemotherapy, received five DC vaccinations at 14-d intervals. The first three vaccinations were administered into the skin, 3 x 106 DCs each subcutaneously and intradermally, followed by two intravenous injections of 6 x 106 and 12 x 106 DCs, respectively. Only minor (less than or equal to grade II) side effects were observed. Immunity to the recall antigen was boosted. Significant expansions of Mage-3A1-specific CD8+ cytotoxic T lymphocyte (CTL) precursors were induced in 8/11 patients. Curiously, these immune responses often declined after the intravenous vaccinations. Regressions of individual metastases (skin, lymph node, lung, and liver) were evident in 6/11 patients. Resolution of skin metastases in two of the patients was accompanied by erythema and CD8+ T cell infiltration, whereas nonregressing lesions lacked CD8+ T cells as well as Mage-3 mRNA expression. This study proves the principle that DC 'vaccines' can frequently expand tumor-specific CTLs and elicit regressions even in advanced cancer and, in addition, provides evidence for an active CD8+ CTL-tumor cell interaction in situ as well as escape by lack of tumor antigen expression.

Comments

Open Access

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