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Induction of monokine production by tumor cells
1Institut für Immunologie und Genetik Deutsches Krebsforschungszentrum, Heidelberg, FRG.
Abstract:
Cells of the proerythromyeloid cell line K562 and of the T cell line Jurkat were able to induce an increase in TNF-, IL1 alpha-, and IL1 beta-mRNA expression in human peripheral blood derived monocytes in vitro. The activating principle of these tumor cells was associated with fractions of membrane preparations of distinct molecular mass, 32-38 kD for Jurkat cells and 46-54 kD for K562 cells, respectively. At least part of the activating constituent seemed to be protein in nature. Isolated membrane preparations of both cell types induced production and secretion of TNF. Stimulation of monocytes with the viable tumor cells led to TNF release only when Jurkat cells were used. Viable K562 cells induced enhanced TNFmRNA expression but seemed to absorb soluble TNF from the supernatant.
Insights
Tumor cell membrane preparations activate human monocytes to express inflammatory cytokine mRNA, including tumor necrosis factor (TNF). This activation involves protein components and varies between Jurkat and K562 cell lines.
Area of Science:
- Immunology
- Cell Biology
Background:
- Human peripheral blood monocytes play a crucial role in immune responses.
- Tumor cells can modulate immune cell activity.
- Cytokines like TNF-alpha, IL-1 alpha, and IL-1 beta are key inflammatory mediators.
Purpose of the Study:
- To investigate the effect of K562 and Jurkat tumor cell lines on monocyte cytokine expression.
- To identify the components within tumor cells responsible for monocyte activation.
Main Methods:
- Co-culture of human peripheral blood monocytes with K562 and Jurkat cell lines in vitro.
- Analysis of tumor cell membrane preparations for activating substances.
- Measurement of TNF-, IL1 alpha-, and IL1 beta-mRNA expression in monocytes.
- Assessment of TNF production and secretion.
Main Results:
- Both K562 and Jurkat cells induced increased TNF-, IL1 alpha-, and IL1 beta-mRNA expression in monocytes.
- Activating substances were found in membrane preparations, with distinct molecular masses for each cell type (Jurkat: 32-38 kD; K562: 46-54 kD).
- The activating component appeared to be proteinaceous.
- Isolated membrane preparations induced TNF production and secretion.
- Viable Jurkat cells stimulated TNF release from monocytes, while viable K562 cells induced mRNA expression but appeared to absorb soluble TNF.
Conclusions:
- Tumor cell membranes contain proteinaceous factors that activate monocytes to upregulate inflammatory cytokine mRNA.
- The molecular characteristics of these activating factors differ between Jurkat and K562 cells.
- Viable tumor cells differentially affect monocyte TNF release, with K562 cells potentially interfering with secreted TNF.