C57BL/6 mice were sensitized and challenged with OVA for 7 days to induce AAD or 6 weeks to induce a state of LIT. Serum from AAD or LIT mice, diluted to achieve equivalent levels of total OVA-specific IgE, was used to sensitize rat basophil leukemia cells for allergen-mediated degranulation. Levels of degranulation were measured in relation to serum concentrations of free IgE and IgG anti-IgE/IgE immune complexes.
On careful analysis, it was observed that the serum from AAD animals induced a greater degree of basophil degranulation in comparison to the serum from LIT animals. The obtained results correlated with higher levels of free IgE in AAD animals, whereas LIT mice demonstrated a significant increase in IgG anti-IgE/IgE immune complexes relative to their diseased counterparts.
The study concluded that the sequestration of free IgE by naturally occurring IgG anti-IgE may aid in the development of immune tolerance against inhaled allergens. The decrease in bioavailability of free IgE may, in turn, contribute to the overall reduction of asthma symptoms via a mechanism that mimics the therapeutic effects of humanized IgG anti-IgE.
Reference: https://clinicalmolecularallergy.biomedcentral.com/articles/10.1186/s12948-018-0091-x
