Plattner, Kevin; Gharailoo, Zahra; Zinkhan, Simon; Engeroff, Paul; Bachmann, Martin F; Vogel, Monique (2022). IgE glycans promote anti-IgE IgG autoantibodies that facilitate IgE serum clearance via Fc Receptors. Frontiers in immunology, 13(1069100), p. 1069100. Frontiers Research Foundation 10.3389/fimmu.2022.1069100
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BACKGROUND
Recent studies have shown that IgE glycosylation significantly impacts the ability of IgE to bind to its high-affinity receptor FcεRI and exert effector functions. We have recently demonstrated that immunizing mice with IgE in a complex with an allergen leads to a protective, glycan-dependent anti-IgE response. However, to what extent the glycans on IgE determine the induction of those antibodies and how they facilitate serum clearance is unclear.Therefore, we investigated the role of glycan-specific anti-IgE IgG autoantibodies in regulating serum IgE levels and preventing systemic anaphylaxis by passive immunization.
METHODS
Mice were immunized using glycosylated or deglycosylated IgE-allergen-immune complexes (ICs) to induce anti-IgE IgG antibodies. The anti-IgE IgG antibodies were purified and used for passive immunization.
RESULTS
Glycosylated IgE-ICs induced a significantly higher anti-IgE IgG response and more IgG-secreting plasma cells than deglycosylated IgE-ICs. Passive immunization of IgE-sensitized mice with purified anti-IgE IgG increased the clearance of IgE and prevented systemic anaphylaxis upon allergen challenge. Anti-IgE IgG purified from the serum of mice immunized with deglycosylated IgE-ICs, led to a significantly reduced elimination and protection, confirming that the IgE glycans themselves are the primary drivers of the protectivity induced by the IgE-immune complexes.
CONCLUSION
IgE glycosylation is essential for a robust anti-IgE IgG response and might be an important regulator of serum IgE levels.