Single B-cell deconvolution of peanut-specific antibody responses in allergic patients

Autor: Kari C. Nadeau, Tim J. Looney, Tho D. Pham, Jasmine J. King, Ramona A. Hoh, Jennifer A. Jenks, Katherine J. L. Jackson, Krishna M. Roskin, Robert G. Hamilton, Chen Wang, Ji Yeun Lee, Yi Liu, Scott D. Boyd, Shilpa A. Joshi, Shu Chen Lyu, Vaishali P. Dixit
Rok vydání: 2016
Předmět:
Zdroj: Journal of Allergy and Clinical Immunology. 137:157-167
ISSN: 0091-6749
DOI: 10.1016/j.jaci.2015.05.029
Popis: Background The frequencies, cellular phenotypes, epitope specificity, and clonal diversity of allergen-specific B cells in patients with food allergy are not fully understood but are of major pathogenic and therapeutic significance. Objective We sought to characterize peanut allergen–specific B-cell populations and the sequences and binding activities of their antibodies before and during immunotherapy. Methods B cells binding fluorescently labeled Ara h 1 or Ara h 2 were phenotyped and isolated by means of flow cytometric sorting from 18 patients at baseline and 13 patients during therapy. Fifty-seven mAbs derived from allergen-binding single B cells were evaluated by using ELISA, Western blotting, and peptide epitope mapping. Deep sequencing of the B-cell repertoires identified additional members of the allergen-specific B-cell clones. Results Median allergen-binding B-cell frequencies were 0.0097% (Ara h 1) or 0.029% (Ara h 2) of B cells in baseline blood from allergic patients and approximately 3-fold higher during immunotherapy. Five of 57 allergen-specific cells belonged to clones containing IgE-expressing members. Almost all allergen-specific antibodies were mutated, and binding to both conformational and linear allergen epitopes was detected. Increasing somatic mutation of IgG 4 members of a clone was seen in immunotherapy, whereas IgE mutation levels in the clone did not increase. Conclusion Most peanut allergen–binding B cells isolated by means of antigen-specific flow sorting express mutated and isotype-switched antibodies. Immunotherapy increases their frequency in the blood, and even narrowly defined allergen epitopes are recognized by numerous distinct B-cell clones in a patient. The results also suggest that oral immunotherapy can stimulate somatic mutation of allergen-specific IgG 4 .
Databáze: OpenAIRE