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Interleukin-4 is an autocrine growth factor secreted by the L-428 Reed-Sternberg cell
1Department of Medicine, Emory University School of Medicine, Atlanta, GA 30303.
Blood
|January 1, 1992
Summary
Reed-Sternberg cells in Hodgkin's disease secrete a growth factor similar to interleukin-4 (IL-4). While IL-4 acts as an autocrine factor, blocking it did not inhibit cell growth, suggesting alternative proliferation mechanisms in these cancer cells.
Area of Science:
- Immunology
- Cell Biology
- Oncology
Background:
- Reed-Sternberg (RS) cells in Hodgkin's disease resemble activated lymphocytes.
- Lymphokines from activated lymphocytes stimulate L-428 RS cell proliferation.
Purpose of the Study:
- To investigate the nature of lymphokines secreted by L-428 RS cells.
- To determine if these secreted factors are autocrine growth factors for RS cells.
Main Methods:
- Characterization of secreted lymphokine by molecular weight and Western immunoblotting.
- Assessment of antibody neutralization and receptor competition assays.
- Quantification of IL-4 receptors on L-428 cells.
- Analysis of IL-4 mRNA expression in L-428 cells.
Main Results:
- L-428 cells secrete a lymphokine (Hodgkin's cell growth factor, HCGF) with characteristics of interleukin-4 (IL-4).
- HCGF binds to IL-4 receptors on L-428 cells, which possess approximately 3,396 high-affinity receptor sites/cell.
- L-428 cells express mRNA for IL-4, indicating autocrine IL-4 production.
- Despite evidence for IL-4's role, anti-IL-4 antibodies did not inhibit sustained serum-free growth of L-428 cells.
Conclusions:
- Interleukin-4 (IL-4) is likely an autocrine growth factor for L-428 RS cells in Hodgkin's disease.
- The lack of growth inhibition by anti-IL-4 suggests potential protection of the IL-4 receptor complex or alternative growth pathways.