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Spontaneous membrane transfer through homotypic synapses between lymphoma cells.
Mary Poupot1, Jean-Jacques Fournié
1Département Oncogénèse and Signalisation dans les Cellules Hématopoiétiques, Unité 563 de l'Institut National de la Santé et de la Recherche Médicale, Centre de Physiopathologie de Toulouse Purpan, BP 3028, 31024 Toulouse, France.
Journal of Immunology (Baltimore, Md. : 1950)
|August 21, 2003
Summary
Resting healthy cells are inactive, but some leukemia cell lines, like Burkitt's lymphoma Daudi, spontaneously transfer cell membranes through immunological synapses. This suggests a previously unknown autoreactivity in certain leukemia cells.
Area of Science:
- Immunology
- Cell Biology
- Cancer Research
Background:
- Immunological synapses facilitate intercellular membrane transfer from target cells to effector cells (T, B, NK cells).
- This transfer typically requires effector cell activation via stimulatory ligand recognition.
- Spontaneous synaptic transfers between homotypic lymphoid cells have not been previously documented.
Purpose of the Study:
- To investigate spontaneous intercellular membrane transfer between homotypic lymphoid cells.
- To determine if leukemia cell lines exhibit unique membrane transfer behaviors.
- To elucidate the mechanisms and conditions underlying spontaneous synaptic transfers.
Main Methods:
- Co-culture of resting healthy lymphoid cells and various tumor cell lines, including leukemia cell lines.
- Analysis of intercellular transfer of membrane fragments using microscopy and biochemical assays.
- Investigation of the role of cell contact, protein kinase C, and mitogen-activated protein/extracellular signal-regulated kinase kinase pathways.
- Assessment of B cell receptor activation effects on membrane transfer.
Main Results:
- Resting healthy lymphoid cells and most tumor cell lines showed no spontaneous membrane transfer without antigen (Ag) stimulation.
- Certain leukemia cell lines, notably Burkitt's lymphoma Daudi, continuously uptake autologous cell membranes.
- This transfer occurs via cell contact, specifically through immunological synapses in homotypic Daudi conjugates, and does not involve cytosolic molecules or exosomes.
- The process involves constitutive protein kinase C and mitogen-activated protein/extracellular signal-regulated kinase kinase activity, significantly enhanced by B cell receptor activation.
Conclusions:
- Spontaneous homosynaptic transfer of autologous cell membranes is a novel phenomenon observed in some leukemia cell lines.
- This autoreactivity may represent a unique characteristic of certain leukemia cells.
- The findings suggest a previously unrecognized mechanism of cell-cell interaction in leukemia.