Related Experiment Videos
Inhibition of human granulocyte-macrophage colony formation by interleukin 2-treated lymphocytes
M Takahashi1, K Oshimi, H Saito
1Department of Medicine, Tokyo Women's Medical College, Japan.
Abstract:
The effects of interleukin 2 (IL-2)-treated lymphocytes on human myeloid progenitors (CFU-GM) were studied. When peripheral blood mononuclear cells (PBMC) were cultured for 3 days with recombinant IL-2, they developed lymphokine-activated killer (LAK) activity against normal bone marrow cells, and also suppressed colony formation by CFU-GM. Suppression of CFU-GM was found to be mediated mainly by natural killer (NK) cells, and to a lesser degree by T cells according to the results showing that isolated NK cells and T cells exhibited strong and moderate suppressor function, respectively. Since the levels of LAK activity and of CFU-GM inhibitory activity were not parallel in each individual, inhibition of CFU-GM does not seem to be due to a direct lytic action by LAK cells. This possibility was supported by our finding that the supernatant of IL-2-treated PBMC contained factor(s) that inhibited CFU-GM colony formation.
Insights
Interleukin 2 (IL-2) treatment of lymphocytes suppressed human myeloid progenitor (CFU-GM) colony formation. This suppression was primarily mediated by natural killer (NK) cells, not direct lymphokine-activated killer (LAK) cell action.
Area of Science:
- Immunology
- Hematology
Background:
- Interleukin 2 (IL-2) is a cytokine that stimulates lymphocytes.
- Human myeloid progenitors, such as colony-forming unit-granulocyte-macrophage (CFU-GM), are crucial for blood cell formation.
- Lymphokine-activated killer (LAK) cells and natural killer (NK) cells are types of lymphocytes with cytotoxic potential.
Purpose of the Study:
- To investigate the effects of IL-2-treated lymphocytes on human myeloid progenitors (CFU-GM).
- To determine the cellular mechanisms responsible for the observed suppression of CFU-GM colony formation.
Main Methods:
- Peripheral blood mononuclear cells (PBMC) were cultured with recombinant IL-2 for 3 days.
- Lymphokine-activated killer (LAK) activity and CFU-GM inhibitory activity were assessed.
- Isolated natural killer (NK) cells and T cells were used to evaluate their suppressor function.
- The effect of supernatant from IL-2-treated PBMC on CFU-GM was analyzed.
Main Results:
- IL-2-treated PBMC exhibited LAK activity and suppressed CFU-GM colony formation.
- Natural killer (NK) cells were the primary mediators of CFU-GM suppression, followed by T cells.
- CFU-GM inhibition levels did not correlate with LAK activity levels, suggesting a non-lytic mechanism.
- Supernatants from IL-2-treated PBMC contained factors that inhibited CFU-GM colony formation.
Conclusions:
- IL-2-treated lymphocytes, particularly NK cells, can suppress human myeloid progenitor function.
- The inhibition of CFU-GM is likely mediated by soluble factors released by lymphocytes rather than direct LAK cell lysis.
- These findings have implications for understanding immune regulation of hematopoiesis.