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Failure to detect IL-3-binding sites on human mast cells
P Valent1, J Besemer, C Sillaber
1I. Medical Department, University of Vienna, Austria.
Journal of Immunology (Baltimore, Md. : 1950)
|November 15, 1990
Summary
Interleukin-3 (IL-3) promotes murine mast cell growth but not human mast cell growth. This suggests human mast cells may have lost high-affinity IL-3 receptors during evolution.
Area of Science:
- Immunology
- Cell Biology
- Hematology
Background:
- Interleukin-3 (IL-3) is a lymphokine known as mast cell growth factor.
- IL-3 promotes growth and differentiation of murine mast cells and activates human basophils.
Purpose of the Study:
- To investigate the expression of IL-3 receptors (IL-3R) on human mast cells.
- To determine if human mast cells respond to IL-3.
Main Methods:
- Binding studies using 125I-radiolabeled human recombinant IL-3 (rIL-3).
- Experiments conducted on a human mast cell line (HMC-1) and purified human lung mast cells.
- Assays for [3H]thymidine uptake, histamine synthesis, histamine releasability, and mast cell differentiation antigen expression.
Main Results:
- Human mast cells (HMC-1 and purified lung mast cells) did not specifically bind radiolabeled human rIL-3.
- Human rIL-3 did not induce proliferation, histamine synthesis, or alter differentiation antigen expression in human mast cells.
Conclusions:
- Human mast cells do not appear to express functional high-affinity IL-3 binding sites.
- A potential evolutionary loss of IL-3 binding sites may explain the difference in IL-3 response between human and murine mast cells.