Enhancement of Anti‐tumor Activity of Natural Killer Cells by BALL‐1, a B Cell Lymphoma Line

Abstract

Vose et al.3) and Vanky et al. 4,5) have succeeded in the induction of autologous tumor-specific cytotoxic lymphocytes by using mixed cultures of peripheral blood mononuclear cells (PBMC) with untreated autologous tumor cells. Grimm et al. 6) and Lotze et al. 7) have shown that lymphokine-activated killer (LAK) cells are induced by culturing PBMC in interleukin-2 (IL-2)-containing medium. Since IL-2 provides the second signal for the proliferation and differentiation of activated T lymphocytes, 8,9) the factor enhances proliferation of the effector T lymphocytes in vitro in the presence of autologous tumor stimulator cells. [10][11][12] Much interest has been focused on the relationships among surface phenotype, major histocompatibility complex restriction for antigen recognition, and the effector function of tumor-specific cytotoxic T lymphocyte subsets. [3][4][5][13][14][15] The induction of nonspecific cytotoxicity is thought to be convenient and effective in cancer immunotherapy. Recent advances in genetic engineering have made it easy to obtain large amounts of pure recombinant cytokines. The world-wide use of these cytokines in cancer immunotherapy is expected to provide much data not only about their usefulness, but also about some hazardous side effects that limit their clinical applications.In our previous paper, we have shown that some glycoproteins of BALL-1 (a B cell line) cells stimulate CD4-positive T cells to produce a unique eosinophil chemotactic factor and a fibroblast proliferation factor. [16][17][18] We report here that some glycoproteins of BALL-1 not only stimulate CD4-positive T cells, but also enhance natural killer (NK) cell-mediated non-specific and cytokine-independent anti-tumor activity.