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Staphylococcal enterotoxin B up-regulates interleukin-2 receptor beta chain expression on tonsillar B cells
1Immunodeficiency Diseases Research Group, Clinical Research Centre, Harrow, GB.
European Journal of Immunology
|October 1, 1993
Summary
Staphylococcal enterotoxin B (SEB) activates B cells by increasing interleukin-2 receptor (IL-2R) beta chain expression, making them responsive to IL-2. This mechanism explains how bacterial superantigens stimulate B cell proliferation.
Area of Science:
- Immunology
- Microbiology
Background:
- Bacterial superantigens, such as staphylococcal enterotoxin B (SEB), are potent activators of the immune system.
- Interleukin-2 receptor (IL-2R) signaling is crucial for T cell proliferation and function, and its role in B cell activation is less understood.
Purpose of the Study:
- To investigate the effect of SEB on IL-2R expression in human B cells.
- To determine if SEB-induced IL-2R expression renders B cells sensitive to IL-2 and promotes DNA synthesis.
Main Methods:
- Human tonsillar B cells, depleted of T cells, were treated with SEB.
- Expression of IL-2R alpha (CD25) and beta (p70) chains was analyzed.
- DNA synthesis was measured in response to IL-2.
Main Results:
- SEB selectively up-regulated the IL-2R beta chain (p70) on B cells, but not the alpha chain (CD25).
- SEB-treated B cells exhibited vigorous DNA synthesis in the presence of low concentrations of IL-2.
- SEB-induced B cell activation is likely mediated by binding to major histocompatibility complex class II molecules.
Conclusions:
- SEB activates B cells by up-regulating IL-2R beta chain expression, rendering them sensitive to IL-2.
- This mechanism contributes to the broad activation of B cells by bacterial superantigens.
- The findings may reflect mechanisms involved in cognate T cell/B cell interactions.