Interferon production and activation of non-specific effector cells by stimulation with lymphoblastoid cell lines in vitro.

A population of non-specific effector lymphocytes is generated in response to stimulation with lymphoblastoid cell lines (LCL). These cytotoxic cells have an activity analogous to that exhibited by natural killer (NK) cells. When lymphoid cells lines established by transformation with Epstein-Barr virus (EBV) are used to stimulate autochthonous T-cell-enriched lymphocytes, the activity against the NK-sensitive target, K562, is increased up to 14-fold. The stimulated T lymphocytes produce interferon, and this factor augments the cytotoxic activity of unstimulated cells. The size distribution of cytotoxic lymphocytes after stimulation with the autochthonous EBV line is unlike that of either T-cells or interferon-augmented T-cells. Autochthonous stimulated lymphocytes which kill K562 are of several size classes, and are included in populations containing large blast cells. In contrast, the K562 activity of both unstimulated T-cells and interferon-augmented T-cells is contained in a more discrete population of cells, just slightly larger than the majority of lymphocytes. Thus, the generation of non-specific effector cells during stimulation with lymphoblastoid cell lines appears to involve the activation of a population of blast-size cells in addition to those initially responsive to interferon augmentation.