The influence of different isolation procedures and the use of target cells from melanoma cell lines and short-term cultures on the non-specific cytotoxic effects of lymphocytes from healthy donors.

In parallel studies the effects of FHL1 and PNL on plated melanoma cells from cell lines and short-term cultures were compared. FHL showed more frequent and also stronger cytotoxic and/or growth-inhibiting effects than PNL. On melanoma target cells from cell lines both FHL and PNL showed more frequent and stronger cytotoxic and/or growth-inhibiting effects than on melanoma target cells from short-term cultures. In the individual donors the percentage of monocytes and EAC-rosette-forming cells in FHL was significantly higher than in PNL. A significant correlation was found between multiplication of the melanoma target cells during the period and an increased susceptibility towards lymphocytes from healthy donors. Melanoma target cells from cell lines were not more fragile, or more susceptible to unfavourable culture conditions than cells from short-term cultures, since non-lymphocytic "effector" cells showed much weaker cytotoxic and/or growth-inhibiting effects than lymphocytes from healthy donors. Cytotoxic effects of lymphocytes from healthy donors were also registered on target cells from a mammary carcinoma and an osteosarcoma cell line. No significant differences in the cytotoxic effects of lymphocytes from healthy donor were observed when tested on mycoplasma-contaminated melanoma cells and the same cells made mycoplasma-free. Mitomycin-C-treated lymphocytes retained their cytotoxic effects. Lymphocytes from a healthy donor tested on different occasions on the same melanoma cells from a short-term culture showed an incidental cytotoxic reaction.