Characterization of dendritic cells generated from peripheral blood of patients with malignant melanoma

Dendritic cells (DCs) are professional antigen presenting cells. Two x 10⁷ peripheral blood mononuclear cells (PBMCs) from each of 6 melanoma patients and 4 normal donors were incubated in 6-well plates. The adherent cells were cultured in GM-CSF (800 U/ml) and IL-4 (1000 U/ml) for 10 days. Anti-CD80, anti-CD86, anti-HLA-DR, anti-HLA-class I monoclonal antibodies and supernatant from two melanoma cell lines were incubated with DCs before responder T cells were added in mixed lymphocyte reaction (MLR). The mean yields of DCs were 3.6 x 10⁵ and 9.3 x 10⁵ for donor and the melanoma patients respectively. MLR was inhibited by anti-CD80, anti-CD86, anti-HLA-DR, anti-HLA-Class I and supernatant of melanoma cultures. The characteristics of DCs generated from melanoma patients were comparable to those from donors. DC function was inhibited by soluble factors in melanoma cultures. Further studies are warranted to characterize these inhibitory factors.