DNA-protein cell content of lymphokine activated killer (L.A.K.) and target cells in co-culture.

An extensive study of the interactions between LAK-target cells in cocultures was performed by means of cytometric (relative DNA and protein content) and morphological parameters. The aim was to obtain new information about the cell cycle stage of tumor target cells (Chang line) during the attack of LAK cells. Specimens obtained from cocultures at 0, 24, 48 hours were processed for electron microscopy, flow cytometry, immunocytochemistry (anti-BrdU reaction) and light microscopy (L.I., M.I., cell-cell interaction). The most intense activity of LAK cells against the target was found at 24 hours of coculture independently of the proliferative stage of the tumor cells. These results suggest that the high affinity between killer and target cells was not affected by the molecular changes of the Chang cell surface during the cell cycle