Peanut oral immunotherapy transiently expands circulating Ara h 2–specific B cells with a homologous repertoire in unrelated subjects

• Published in: Journal of allergy and clinical immunology Vol. 136; no. 1; pp. 125 - 134.e12
• Main Authors: Patil, Sarita U., Ogunniyi, Adebola O., Calatroni, Agustin, Tadigotla, Vasisht R., Ruiter, Bert, Ma, Alex, Moon, James, Love, J. Christopher, Shreffler, Wayne G.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.07.2015; Elsevier Limited
• Subjects: 2S Albumins, Plant - immunology; Administration, Oral; Adolescent; Allergies; Allergy and Immunology; Antibody Formation; antibody repertoire; antigen-specific B cells; Antigens; Antigens, Plant - immunology; Arachis hypogaea; B-Lymphocytes - immunology; Cell Proliferation; Cells, Cultured; Child; Clinical outcomes; Clone Cells; Cloning; Desensitization, Immunologic - methods; Epitopes - immunology; Female; Food allergies; food allergy; Gene amplification; Glycoproteins - immunology; Humans; Immunoglobulin E - immunology; Immunoglobulins; Immunologic Memory; Immunotherapy; Lymphocyte Activation; Male; peanut allergy; Peanut Hypersensitivity - immunology; Peanut Hypersensitivity - therapy; Peanuts; BCR; CDR; peanut allergy; APC; Immunotherapy; PNOIT; antigen-specific B cells; NGS; OIT; food allergy; antibody repertoire; Peanut oral immunotherapy; B-cell receptor; Oral immunotherapy; Next-generation sequencing; Complementarity-determining region; Allophycocyanin
• DOI: 10.1016/j.jaci.2015.03.026
• ISSN: 0091-6749

Peanut oral immunotherapy (PNOIT) induces persistent tolerance to peanut in a subset of patients and induces specific antibodies that might play a role in clinical protection. However, the contribution of induced antibody clones to clinical tolerance in PNOIT is unknown. We hypothesized that PNOIT induces a clonal, allergen-specific B-cell response that could serve as a surrogate for clinical outcomes. We used a fluorescent Ara h 2 multimer for affinity selection of Ara h 2–specific B cells and subsequent single-cell immunoglobulin amplification. The diversity of related clones was evaluated by means of next-generation sequencing of immunoglobulin heavy chains from circulating memory B cells with 2x250 paired-end sequencing on the Illumina MiSeq platform. Expression of class-switched antibodies from Ara h 2–positive cells confirms enrichment for Ara h 2 specificity. PNOIT induces an early and transient expansion of circulating Ara h 2–specific memory B cells that peaks at week 7. Ara h 2–specific sequences from memory cells have rates of nonsilent mutations consistent with affinity maturation. The repertoire of Ara h 2–specific antibodies is oligoclonal. Next-generation sequencing–based repertoire analysis of circulating memory B cells reveals evidence for convergent selection of related sequences in 3 unrelated subjects, suggesting the presence of similar Ara h 2–specific B-cell clones. Using a novel affinity selection approach to identify antigen-specific B cells, we demonstrate that the early PNOIT-induced Ara h 2–specific B-cell receptor repertoire is oligoclonal and somatically hypermutated and shares similar clonal groups among unrelated subjects consistent with convergent selection.