MilliporeSigma
  • Phenotypic determinism and stochasticity in antibody repertoires of clonally expanded plasma cells.

Phenotypic determinism and stochasticity in antibody repertoires of clonally expanded plasma cells.

Proceedings of the National Academy of Sciences of the United States of America (2022-04-30)
Daniel Neumeier, Alexander Yermanos, Andreas Agrafiotis, Lucia Csepregi, Tasnia Chowdhury, Roy A Ehling, Raphael Kuhn, Tudor-Stefan Cotet, Raphaël Brisset-Di Roberto, Mariangela Di Tacchio, Renan Antonialli, Dale Starkie, Daniel J Lightwood, Annette Oxenius, Sai T Reddy
ABSTRACT

The capacity of humoral B cell-mediated immunity to effectively respond to and protect against pathogenic infections is largely driven by the presence of a diverse repertoire of polyclonal antibodies in the serum, which are produced by plasma cells (PCs). Recent studies have started to reveal the balance between deterministic mechanisms and stochasticity of antibody repertoires on a genotypic level (i.e., clonal diversity, somatic hypermutation, and germline gene usage). However, it remains unclear if clonal selection and expansion of PCs follow any deterministic rules or are stochastic with regards to phenotypic antibody properties (i.e., antigen-binding, affinity, and epitope specificity). Here, we report on the in-depth genotypic and phenotypic characterization of clonally expanded PC antibody repertoires following protein immunization. We find that clonal expansion drives antigen specificity of the most expanded clones (top ∼10), whereas among the rest of the clonal repertoire antigen specificity is stochastic. Furthermore, we report both on a polyclonal repertoire and clonal lineage level that antibody-antigen binding affinity does not correlate with clonal expansion or somatic hypermutation. Last, we provide evidence for convergence toward targeting dominant epitopes despite clonal sequence diversity among the most expanded clones. Our results highlight the extent to which clonal expansion can be ascribed to antigen binding, affinity, and epitope specificity, and they have implications for the assessment of effective vaccines.

MATERIALS
Product Number
Brand
Product Description

Protein G GraviTrap, Cytiva 28-9852-55, pack of 10 × 1 mL
Sigma-Aldrich
Albumin from chicken egg white, lyophilized powder, ≥98% (agarose gel electrophoresis)
Sigma-Aldrich
Anti-Mouse IgG (Fc specific)–Peroxidase antibody produced in goat, affinity isolated antibody, buffered aqueous solution
Sigma-Aldrich
Anti-Mouse IgM (μ-chain specific) antibody produced in goat, affinity isolated antibody, lyophilized powder