B-cell receptor ligation selectively inhibits IgE class switch recombination.

Area of Science:

• Immunology
• Molecular Biology

Background:

• Mechanisms limiting class switch recombination (CSR) to IgE may restrict IgE antibody production in allergic diseases.
• B cell receptor (BCR) signaling plays a role in IgE regulation, with prior studies showing it can inhibit CSR.

Purpose of the Study:

• To determine if BCR signaling selectively inhibits IgE CSR.

Main Methods:

• Assessed BCR signaling strength effects on IgE responses in immunized mice.
• Used primary mouse and human B cells induced to switch to IgE in culture.
• Perturbed cells with antibodies, cognate antigen, signaling inhibitors, and cytokines.
• Analyzed results using flow cytometry and RNA analysis.

Main Results:

• In immunized mice, BCR signaling strength inversely correlated with IgE-switched B cell frequencies.
• BCR signaling selectively inhibited IgE CSR in mouse B cells, dependent on ligand properties.
• Syk was required for inhibition; PI3K blockade increased IgE frequencies.
• IL-21 or TGFβ1 with BCR ligation cooperatively inhibited IgE CSR in mouse and human B cells.

Conclusions:

• IgE CSR is uniquely susceptible to inhibition by BCR signaling in both mouse and human B cells.
• These findings have significant implications for the regulation and pathogenesis of allergic diseases.