We then selected patient-derived, tumor-specific antibodies in order to further evaluate their reactivity to melanoma cells, and conducted a preliminary assessment of the potential functional capabilities of a patient-derived antibody from this screen. B cell culture wells were selected based on stringent criteria (OD . 75% positive control antibody), using the cell-based ELISA. Tumor specificity of antibody cultures was evaluated by comparing binding of antibodies from these cultures against multiple melanoma cells (A-375, SK-MEL-2, WM-115) versus normal cells ( Figure 5 , A). We observed multiple antibody cultures with a higher degree of binding to some melanoma cells compared to melanocytes from the same patient (Patient 3, Figure 5 , A; a selection of five of these cultures is shown on Figure 5 , B). Similar results were obtained when we screened for tumor-specific cultures from different patients against melanoma cells and melanocytes. Positive cultures with different binding patterns against four melanoma cell lines (A-375, SK-MEL-2, SK-MEL-28, WM-115) and primary human melanocytes were detected (selected cultures derived from Patients 2, 3, 4 and 6 are shown as examples in Figure 5 , C), reflecting specificity and reactivity of different antibodies to a range of antigens expressed at different levels in a number of melanoma cell lines, and some reactivity to antigens lowly expressed on human melanocytes. Selection of a tumorpositive antibody culture for sub-cloning and limiting dilution was based on degree of reactivity to melanoma cells relative to melanocytes ( Figure 5 , C).