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Control of prothymocyte proliferation by thymic accessory cells
M Papiernik1, C Penit, S el Rouby
1INSERM U 25, CNRS LA 122, Hôpital Necker, Paris, France.
European Journal of Immunology
|September 1, 1987
Summary
Phagocytic thymic reticulum cells, with cell-to-cell contact, induce double-negative (DN) thymocyte proliferation using recombinant interleukin-2 (rIL-2). These accessory cells provide essential signals for DN thymocyte response to IL-2, crucial for T cell development.
Area of Science:
- Immunology
- Cell Biology
- Developmental Biology
Background:
- Thymocyte subpopulations originate from double-negative (DN) precursors.
- DN cells express interleukin-2 receptors (IL-2R) but show poor IL-2 responsiveness.
- The in vivo signal driving DN cell proliferation in response to IL-2 is not well understood.
Purpose of the Study:
- To investigate the role of thymic accessory cells in inducing DN thymocyte proliferation.
- To elucidate the mechanism by which DN thymocytes respond to IL-2.
Main Methods:
- Co-culture of DN thymocytes with phagocytic thymic reticulum cells.
- Use of recombinant IL-2 (rIL-2) as a stimulus.
- Cell proliferation assessed by bromodeoxyuridine labeling.
- Inhibition studies using antibodies against MHC antigens.
Main Results:
- Phagocytic thymic accessory cells induce DN thymocyte proliferation in the presence of rIL-2, requiring cell-to-cell contact.
- Antibodies against MHC class I, but not class II, inhibit this proliferation.
- Accessory cells and rIL-2 are essential for DN cell survival and continuous generation of Lyt-2+ and/or L3T4+ cells.
Conclusions:
- Thymic accessory cells provide critical signals for IL-2-induced proliferation of thymocyte precursors.
- These findings offer insights into normal intrathymic proliferation and differentiation processes.
- Cell-to-cell contact and MHC class I interactions are important for DN thymocyte activation.