An interferon resistant variant of the hairy-cell leukemic cell line, Eskol: biochemical and immunological characterization.

The B-lymphoblastoid cell line Eskol, which is composed of differentiated cells resembling hairy-cell leukemia, has been used to study the effects of type I interferon in vitro. In order to study the mechanism of delayed interferon therapy resistance, a hairy-cell leukemia-like clonal cell line (IREs-4) was isolated from Eskol after 4 months of exposure to r-metIFN-con1. When compared to Eskol cells, the IREs-4 cells were resistant to the antiproliferative effect of type I interferons as well as interferon induced protection against LAK cells.

Interferon--a major regulator of natural killer cell-mediated cytotoxicity.

Natural killer (NK) cells probably function as an early defense line against viruses because of their ability to kill virus-infected cells as well as a variety of tumor cells. In both cases, the killing is major histocompatibility complex (MHC)-unrestricted. NK cells exhibit spontaneous activity but they are positively regulated by interferons (IFNs) or indirectly by such IFN inducers as viruses, bacterial products, poly(rI):(rC), and mitogens.

Interleukin 2 protects hairy leukemic cells from lymphokine-activated killer cell-mediated cytotoxicity.

Interleukin 2 (IL-2) activates natural killer cells and generates lymphokine-activated killer (LAK) cell-mediated cytotoxicity. In "adoptive immunotherapy," a combination of LAK administration and IL-2 infusion was found to be effective therapy for some tumors and ineffective for others. Here we report a novel function for IL-2, its ability to protect tumor cells (cell lines obtained from hairy cell leukemia patients) against LAK activity.

Combination treatment of 2-chlorodeoxyadenosine and type I interferon on hairy cell leukemia-like cells: cytotoxic effect and MHC-unrestricted killer cell regulation.

Hairy cell leukemia (HCL) is a lymphoproliferative disorder of B lymphocytes. Interferons (IFNs), especially of the alpha (alpha) subtype, have shown a significant antitumor effect in HCL patients. However, the therapeutic effect of IFN-alpha is still rather limited.

Dual effects of cytokines in regulation of MHC-unrestricted cell mediated cytotoxicity.

Natural killer (NK) cells probably function as an early defense line against viruses, due to their ability to kill virus-infected cells without resorting to clonal proliferation of memory cells. NK cells are also capable of killing tumor cells. In both cases the killing is major histocompatibility complex (MHC) unrestricted.