Features of the in Vitro Established Rat Large Granular Lymphocyte Leukaemia RNK‐16

A large granular lymphocyte (LGL) leukaemia cell line from the Fisher/F344 rat strain called RNK‐16 has been established in vitro, maintaining the same surface markers as the tumour cell growing in vivo. The tumour has also maintained its specificity pattern and cytotoxic reactivity and serves as a suitable source of natural killer (NK)‐like effector cells in vitro. The cells show no evidence of dependency on, or production of, interleukin 2 or interferons, not is the cytotoxic capacity influenced by treatment with mitogens. The in vitro line does not produce natural killer cytotoxic factor (NKCF) in a constitutive manner, hut can be induced to do so via coculture with tumour target cells. When the fine specificity patterns were analysed, the RNK‐16 cells express species‐preferential lysis of susceptible target cells and a highly discriminatory power to kill only 1 out of 5 rat erythroleukaemia cell lines. When testing normal target susceptibility patterns. RNK‐16 kills lymphoblasts of B type better than T blasts, which is well in line with previous findings on normal NK cell specificity patterns.