Monoclonal Anti-MAGE-3 CTL Responses in Melanoma Patients Displaying Tumor Regression after Vaccination with a Recombinant Canarypox Virus

Abstract

We have analyzed the T cell responses of HLA-A1 metastatic melanoma patients with detectable disease, following vaccination with a recombinant ALVAC virus, which bears short MAGE-1 and MAGE-3 sequences coding for antigenic peptides presented by HLA-A1. To evaluate the anti-MAGE CTL responses, we resorted to antigenic stimulation of blood lymphocytes under limiting dilution conditions, followed by tetramer analysis and cloning of the tetramer-positive cells. The clones were tested for their specific lytic ability and their TCR sequences were obtained. Four patients who showed tumor regression were analyzed, and an anti-MAGE-3.A1 CTL response was observed in three of these patients. Postvaccination frequencies of anti-MAGE-3.A1 CTL were 3 × 10−6, 3 × 10−3, and 3 × 10−7 of the blood CD8 T cells, respectively. These three responses were monoclonal. No anti-MAGE-1.A1 CTL response was observed. These results indicate that, like peptide immunization, ALVAC immunization produces monoclonal responses. They also suggest that low-level antivaccine CTL responses can initiate a tumor regression process. Taken together, our analysis of anti-MAGE-3.A1 T cell responses following peptide or ALVAC vaccination shows a degree of correlation between CTL response and tumor regression, but firm conclusions will require larger numbers.

Promoter Demethylation and Histone Acetylation Mediate Gene Expression of MAGE-A1, -A2, -A3, and -A12 in Human Cancer Cells

“…Recent clinical studies could show that an immunotherapy with MAGE peptides had a minimal toxicity and caused induction of tumor-specific CTLs (35)(36)(37)(38). A significant tumor regression could also be observed in several patients, pointing out that a vaccination with a MAGE-A peptide could be promising for the treatment of tumor patients.…”

Polyclonal CTL Responses Observed in Melanoma Patients Vaccinated with Dendritic Cells Pulsed with a MAGE-3.A1 Peptide

“…After washing, they were distributed at 1 ϫ 10 4 -3 ϫ 10 4 cells/0.2 ml in microwells containing Iscove's medium with 10% HS, IL-2 (20 U/ml), IL-7 (10 ng/ml; R&D Systems, Minneapolis, MN). At variance with Karanikas et al (6), MAGE-3.A1 peptide at 1 M was added to the microculture. In some experiments, IL-4 was added at 10 U/ml.…”

“…CD8 ϩ tetramer ϩ cells were sorted, cloned at one cell per well, and restimulated under conditions that were very similar to those described by Karanikas et al (6), with some differences in the number of stimulator cells and the cells used as feeder cells. Sorted cells were stimulated by the addition of irradiated (100 Gy) peptide-pulsed (20 M for 60 min at room temperature, washed) cells, either 10 4 MZ2-MEL-3.0 HLA-A1 melanoma cells or 3 ϫ 10 4 allogenic HLA-A1 EBV-transformed B cells.…”

“…We resorted to an approach based on stimulation of blood lymphocyte microcultures with the antigenic peptide, followed by labeling of the microcultures with an A1/MAGE-3 tetramer (5). Among 10 regressing HLA-A1 patients who were evaluated, 5 showed an anti-MAGE-3.A1 CTL response (5,6). The intensity of these responses varied widely, with CTL precursor (CTLp) 3 frequencies ranging from 4 ϫ 10 Ϫ7 to 10 Ϫ3 among blood CD8 cells.…”

Two new tumor‐specific antigenic peptides encoded by gene MAGE‐C2 and presented to cytolytic T lymphocytes by HLA‐A2

“…Melanoma patient EB81 showed complete regression of cutaneous metastatic lesions after repetitive vaccination with a recombinant canarypox virus of the ALVAC type encoding 2 HLA-A1-restricted peptides derived from MAGE-A1 and MAGE-A3. 14,15 This regression has been durable and was associated with a monoclonal CTL response to one of the vaccine antigens, the MAGE-A3 peptide. We established a tumor cell line from an invaded lymph node that had been resected from this patient, and we used it to stimulate autologous blood lymphocytes collected at the time of tumor regression.…”