RESUMEN
Dialysable human leukocyte extract (10 kDa molecular weight cutoff) contained a basic factor stimulating natural killer (NK) cytotoxicity of human peripheral blood mononuclear cells (PBMC) against human K562 tumor cells when PBMC were pre-incubated with the factor for 72h prior to cytotoxicity assays. This cytotoxicity-stimulating factor (CySF-L2) could be enriched by adsorption to ion exchange resin Dowex 50WX2 (H-form) eluting at pH 9.0-9.6 when a pH gradient between pH 3 and pH 10 was used. Further purification was achieved by chromatography on DEAE-Sepharose. The factor has a molecular weight of approximately 1000 Da and is insensitive to protease and exopeptidase treatment but sensitive against treatment with endoglycosidase F. Using immunomagnetic cell sorting, complement-mediated cell depletion and depletion by planning, the cytotoxic effector cells activated during pre-incubation of PBMC with CySF-L2 could be identified as CD16+ CD14+ monocytes/macrophages and as Leu7+ Leu19+ CD16+ CD3- CD8- NK cells.
Asunto(s)
Citotoxicidad Inmunológica/efectos de los fármacos , Células Asesinas Naturales/inmunología , Monocitos/inmunología , Extractos de Tejidos/farmacología , Adulto , Factores de Edad , Femenino , Humanos , Células Asesinas Naturales/efectos de los fármacos , Leucemia Mielógena Crónica BCR-ABL Positiva , Masculino , Persona de Mediana Edad , Valores de Referencia , Factores Sexuales , Células Tumorales Cultivadas/inmunologíaRESUMEN
The mechanism of natural killer (NK) cytotoxicity activation of human peripheral blood mononuclear cells (PBMC) by CySF-L2 was elucidated. CySF-L2 is a cytotoxicity-stimulating factor isolated from dialysable human leucocyte extract, which activates NK cytotoxicity against NK-sensitive and insensitive tumour cells (K562; Daudi; Raji; MOLT4) when preincubated with effector cells for 72 h. CySF-L2-mediated activation was synergistic to interleukin-2(IL-2)-mediated activation of NK cytotoxicity. Induction of interferon gamma (IFN gamma) release was the crucial step during CySF-L2-mediated NK cytotoxicity activation since enhancement of NK activity was completely blocked when anti-IFN gamma antibodies were present during treatment of PBMC. Anti-IFN alpha, anti-TNF alpha (tumour necrosis factor alpha) anti-IL-1 and anti-IL-2 antibodies showed no blocking effect. Analysis of the supernatant culture medium after 72 h incubation of PBMC and their highly purified subpopulations demonstrated that CySF-L2 induced release of IFN gamma from CD3+T cells and CD56+CD3- NK cells and of TNF alpha and prostaglandin E2 from monocytes. CySF-L2 was also capable of activating NK cytotoxicity of highly purified (98%) CD56+CD3- NK cells as well as of monocytes (94% pure). Cell cooperation studies connected with analysis of cytokine release and enhancement of NK cytotoxicity indicated that CySF-L2 might play an essential role in the up and down regulation of NK cytotoxicity by the cytokine network.