Differential Activation of Lymphokine-activated Killer Cells with Different Surface Phenotypes by Cultivation with Recombinant Interleukin 2 or T-cell Growth Factor in Gastric Cancer Patients

Fourteen days' culture of human peripheral blood lymphocytes (PBL) with recombinant interleukin 2 (rIL 2) or T cell growth factor (TCGF) results in the generation of lymphoklne-activated killer (LAK) effector cells which have the unique property of lysing natural killer (NK)-resistant human tumor cells, Daudi, as well as NK-sensitive, K562 cells. LAK cells were generated from both normal and gastric cancer patients' PBL. However, LAK cell activities induced by rIL 2 or TCGF decreased with the progress of the tumor growth. In addition, TCGF-induced LAK cell activities were found to be lower than the rIL 2-indnced LAK cell activities. Different mechanisms may be involved in the decreases of the rIL 2-induced and TCGF-induced LAK cell activities. This study further demonstrates that the cell types involved are also heterogeneous, as determined by phenotypic characteristics. The LAK-effector cell type was analyzed by two-color flow cytometry. RIL 2-induced LAK cells showed increased proportions of CD4^±Leu 8^- and Leu 7^±CD16^-, and a decreased proportion of CD8^±CD11^- cells, which are believed to be associated with killer T cell functions. In contrast, TCGF-induced LAK cells revealed significantly increased proportions of CD8^±CD11^-and CD4^±Leu 8^- cells, and a decreased proportion of Leu 7^±CD16^- cells. Thus, LAK cells with different surface phenotypes were induced by the cultivations with rIL 2 and with TCGF.