Molecular deconvolution of the monoclonal antibodies that comprise the polyclonal serum response

Yariv Wine, Daniel R. Boutz, Jason J. Lavinder, Aleksandr E. Miklos, Randall A. Hughes, Kam Hon Hoi, Sang Taek Jung, Andrew P. Horton, Ellen M. Murrin, Andrew D. Ellington, Edward M. Marcotte, George Georgiou

Research output: Contribution to journalArticlepeer-review


We have developed and validated a methodology for determining the antibody composition of the polyclonal serum response after immunization. Pepsin-digested serum IgGs were subjected to standard antigen-affinity chromatography, and resulting elution, wash, and flow-through fractions were analyzed by bottom-up, liquid chromatography-high-resolution tandem mass spectrometry. Identification of individual monoclonal antibodies required the generation of a database of IgG variable gene (V-gene) sequences constructed by NextGen sequencing of mature B cells. Antibody V-gene sequences are characterized by short complementarity determining regions (CDRs) of high diversity adjacent to framework regions shared across thousands of IgGs, greatly complicating the identification of antigen-specific IgGs from proteomically observed peptides. By mapping peptides marking unique VH CDRH3 sequences, we identified a set of V-genes heavily enriched in the affinity chromatography elution, constituting the serum polyclonal response. After booster immunization in a rabbit, we find that the antigenspecific serum immune response is oligoclonal, comprising antibodies encoding 34 different CDRH3s that group into 30 distinct antibody VH clonotypes. Of these 34 CDRH3s, 12 account for ∼60% of the antigen-specific CDRH3 peptide mass spectral counts. For comparison, antibodies with 18 different CDRH3s (12 clonotypes) were represented in the antigen-specific IgG fraction from an unimmunized rabbit that fortuitously displayed a moderate titer for BSA. Proteomically identified antibodies were synthesized and shown to display subnanomolar affinities. The ability to deconvolute the polyclonal serum response is likely to be of key importance for analyzing antibody responses after vaccination and for more completely understanding adaptive immune responses in health and disease.

Original languageEnglish
Pages (from-to)2993-2998
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number8
StatePublished - 19 Feb 2013
Externally publishedYes


  • Antibody proteomics
  • Antibody repertoire
  • B-cell response
  • Humoral response
  • Serum immunoprofiling

All Science Journal Classification (ASJC) codes

  • General


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