Blocking function of allergen-specific immunoglobulin G, F(ab')2, and Fab antibodies prepared from patients undergoing Dermatophagoides pteronyssinus immunotherapy

Background: The blocking function of allergen-specific F(ab')(2) [sF(ab')(2)] and Fab (sFab) fragment antibodies prepared from allergen immunotherapy-induced specific immunoglobulin G (sIgG) has not been fully investigated. Objective: To investigate the inhibitory function of sIgG, sF(ab')(2), and sFab antibodies in patients undergoing Dermatophagoides pteronyssinus (Der-p) subcutaneous immunotherapy (SCIT). Methods: This study involved 10 subjects (aged 18-42 years) with house dust mite allergic rhinitis or asthma who received a 156-week course of Der-p SCIT. Total IgG levels were purified from the serum of the participants at weeks 0 and 156 by protein A affinity chromatography. Der-p sIgG was purified by affinity chromatography with Der-p as a ligand at week 156. The sF(ab') 2 and sFab antibodies were prepared from Der-p sIgG by treatment with pepsin and papain, respectively. Furthermore, IgE-facilitated allergen binding assay, basophil activation inhibition test, and cytokine release inhibition assay were used to assess the inhibitory function of Der-p sIgG, sF (ab')(2), and sFab antibodies. Results: We found that the Der-p sIgG, sF(ab')(2), and sFab antibodies markedly blocked Der-p-allergen sIgE complex binding to B cells, inhibited basophil activation, and markedly reduced the production of interleukin (IL)-5, IL-13, IL-17, and tumor necrosis factor-alpha by peripheral blood mononuclear cells. Conclusion: SCIT-induced Der-p sIgG, sF(ab')(2), and sFab antibodies may block the formation of Der-p-sIgE complexes and may serve as a potential allergen-targeted biologics candidate for the treatment of allergic asthma. (C) 2022 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc.