Figure 3. Sequencing the plasmablast antibody repertoires in individuals with RA.
DNA barcoding and next-generation sequencing were used to analyze the plasmablast antibody repertoire of 4 individuals with active, anti-CCP+ RA. A phylogenetic tree of the plasmablast antibody repertoire was generated by concatenating and clustering the heavy- and light-chain sequences of the plasmablast antibodies and arranging them by heavy-chain V-gene family usage. Each peripheral node represents a single antibody. Clonal families of antibodies are indicated by bolded, red lines. The letters RA followed by a number denote an antibody that was selected for cloning and expression, and red font denotes antibodies that exhibited reactivity in the CCP2 assay (Figure 4A) or on RA antigen microarrays (Figure 4B).