Peanut oral immunotherapy transiently expands circulating Ara h 2–specific B cells with a homologous repertoire in unrelated subjects
Background 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. Objective...
| Main Authors: | , , , , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
Elsevier
2017
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| Online Access: | http://hdl.handle.net/1721.1/109437 https://orcid.org/0000-0002-2172-2286 https://orcid.org/0000-0003-0921-3144 |
| Summary: | Background
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.
Objective
We hypothesized that PNOIT induces a clonal, allergen-specific B-cell response that could serve as a surrogate for clinical outcomes.
Methods
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.
Results
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.
Conclusions
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.
Key words
Immunotherapy; antigen-specific B cells; peanut allergy; food allergy; antibody repertoire
Abbreviations used
APC, Allophycocyanin; BCR, B-cell receptor; CDR, Complementarity-determining region; NGS, Next-generation sequencing; OIT, Oral immunotherapy; PNOIT, Peanut oral immunotherapy |
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