Blocking IgE with L-glutamic acid analogs as an alternative approach to allergy treatment

Background: IgE–mediated allergic diseases have increased in the last decades. The most prevalent allergens from castor seeds are Ric c1 and Ric c3, isoforms of 2S albumin. These allergenic proteins cross-react with allergens from peanut, shrimp, fish, corn, gramineous, house dust, and tobacco. The usual allergy treatment employs antihistaminic and, immunotherapies. We propose an alternative immunotherapeutic approach, denoted “IgE-blockage” by L-Glutamic acid or modified-glutamic acid. Methods: Six compounds, D-glutamic acid, L-glutamic acid, N-methyl-L-glutamic acid, N-acetyl-L-glutamic acid, N- (4-nitrobenzoyl) -L-glutamic acid, and N-carbamyl-L-glutamic, were tested as a blocker. To evaluate motor coordination and the sedative/hypnotic activity of L-glutamic acid, a rota-rod test and a thiopental sodium-induced sleeping test were used. Results: the compounds, L- Glutamic acid and L-Nitrobenzoyl glutamic acid, were the most active compounds to block the interaction of castor allergens with IgE. These compounds also prevent cross-responses with allergens from food sources and inhalants that cross-react with them. In the sleeping test, the groups that received L-glutamic acid at doses of 10 and 30 mg/kg had a sleeping time similar to the vehicle control group. No changes in the animals’ behavior were observed and there was no difference between the L-glutamic acid groups and the vehicle control groups in the rota-rod test. Conclusion: L-glutamic acid and L-Nitrobenzoyl glutamic acid could be used as IgE blockers to prevent allergic diseases.