Differential susceptibility of metastatic lymphoma cells to natural immunity

The susceptibility of metastatic variant lymphoma cells to natural immunity was studied using a low malignant/metastatic parental RAW117-P cell line and its liver colonizing highly malignant/metastatic RAW117-H10 cell line. The metastatic variant RAW117-H10 cells express a significantly lower amount of laminin-like and fibronectin-like molecules as determined by flow cytometry using monospecific polyclonal antibodies to laminin and fibronectin. Our studies indicated that the RAW117-H10 cells are resistant to natural killer (NK) cell-mediated cytotoxicity. In vitro activation of the effector cells with interferon-gamma increased the susceptibility of these cells to NK-mediated cytotoxicity while maintaining the difference between the two cell lines. However, when recombinant interleukin-2 was used to activate the effector cells, the cytotoxicity of the lymphokine-activated effector cells to both parental low metastatic RAW117-P cells and highly metastatic RAW117-H10 cells was similar.