A preclinical model to assess the antigenicity of an HLA-A2 melanoma cell vaccine

BACKGROUND: The authors have demonstrated that immunization with melanoma whole-cell vaccine (MCV) augments T-cell responses to melanoma and that cytotoxic T-cells (CTL) recognize allogeneic melanoma-bearing shared HLA-A antigens. A preclinical model was developed to assess CTL activation in vitro using melanoma lines as stimulators. HLA-A2 expression is predominant in melanoma patients and plays a role in HLA class I restricted CTL killing of melanomas. The authors hypothesized that a MCV consisting of allogeneic HLA-A2 melanomas may be as good as autologous melanoma MCV for HLA-A2 patients. METHODS: CTL were generated from peripheral blood lymphocytes of patients with HLA-A2 melanoma by stimulation with autologous melanoma, allogeneic melanoma (HLA-A2 or non-HLA-A2), or allogeneic MCV (mixed HLA-A2 and non-HLA-A2 melanomas). RESULTS: HLA-A2 MCV and autologous melanoma were similar and significantly better stimulators than the others. Specificity also was supported by CTL killing and mixed lymphocyte tumor reaction assays. CONCLUSIONS: These studies provide important information for the studying immunization of patients with HLA-A2 melanoma with an allogeneic HLA-A2 MCV in a Phase I clinical trial.