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Cytokine control of peripheral-blood CD23 expression and sCD23 release: differential regulation by IL-2 and IL-4
1Institut für Medizinische Mikrobiologie und Immunologie, Arbeitsgruppe für Infektabwehrmechanismen, Ruhr-Universität Bochum, BRD.
Insights
Interleukin-2 (IL-2) induces CD23 expression on B cells, distinct from IL-4 effects. Pre-stimulation with Staphylococcus aureus Cowan 1 alters cytokine responses, reducing IL-2-induced CD23 expression.
Area of Science:
- Immunology
- Cell Biology
Background:
- CD23 is a low-affinity receptor for IgE, playing a role in B cell activation and differentiation.
- Cytokines like IL-4 are known to induce CD23 expression on B cells.
Purpose of the Study:
- To investigate the role of Interleukin-2 (IL-2) in inducing CD23 expression on human peripheral-blood lymphocytes (PBL).
- To compare the effects of IL-2 with IL-4 on CD23 expression and soluble CD23 (sCD23) release.
- To examine how pre-stimulation with Staphylococcus aureus Cowan 1 (SAC) affects cytokine-induced CD23 expression.
Main Methods:
- Flow cytometry was used to analyze CD23 expression on peripheral-blood B cells.
- Cytokine stimulation (IL-2, IL-4, Interferon gamma) was performed on PBL with and without SAC pre-treatment.
- Soluble CD23 (sCD23) levels were measured in cell culture supernatants.
Main Results:
- IL-2 significantly induced CD23 expression and sCD23 release on human peripheral-blood B cells.
- IL-2-induced CD23 expression showed kinetic differences compared to IL-4 and was not inhibited by anti-IL-4 antibodies.
- SAC pre-stimulation reduced basal CD23 expression and significantly diminished IL-2-induced CD23 expression and sCD23 release, while IL-4's effect remained comparable.
- Interferon gamma suppressed IL-2-induced CD23 expression on SAC-PBL but not IL-4-induced expression.
- Combined IL-2/IL-4 stimulation inhibited the individual effects of each cytokine on CD23 expression and immunoglobulin synthesis.
Conclusions:
- IL-2 is a novel inducer of CD23 expression and sCD23 release on human B cells, with mechanisms distinct from IL-4.
- B cell activation status, influenced by SAC, modulates the response to IL-2 and IL-4 regarding CD23 expression.
- The interplay between IL-2 and IL-4 can lead to reciprocal inhibition of CD23 expression and immunoglobulin production.
Abstract:
CD23 expression on peripheral-blood lymphocytes (PBL) was studied under the influence of cytokines. It is shown that IL-2 induced CD23 expression on human peripheral-blood B cells. Evidence is presented that the IL-2 induced CD23 expression and release of soluble CD23 (sCD23) are not mediated by IL-4. In comparison to IL-4, the IL-2-induced CD23 expression and sCD23 release revealed kinetic differences and were not inhibited by anti-IL-4. The prestimulation of PBL with Staphylococcus aureus strains Cowan 1 (SAC) led to a pronounced reduction in basal CD23 expression and to a change in the response of cytokines. Subsequent stimulation with IL-4 induced CD23 to the same extent as on unstimulated cells, whereas the IL-2-induced CD23 expression and sCD23 release were greatly reduced. Interferon gamma showed no effects on the IL-4-stimulated CD23 expression of SAC-PBL, whereas the IL-2-induced CD23 expression was suppressed. Furthermore, we demonstrate that the stimulation with IL-2/IL-4 inhibits the effects of the individual cytokine; this inhibition is also seen for immunoglobulin (E, G, M) synthesis.