BCR Sequencing was carried out as described previously (37 (link)). Briefly, whole transcriptome amplification (WTA) was performed on the sorted cell-lysates according to the Smart-Seq2 protocol (105 (link)). We then amplified heavy and light chain sequences from the WTA products utilizing pools of partially degenerate pools of V region specific primers (Qiagen HotStar Taq Plus). Heavy and light chain amplifications were carried out separately, with each pool containing pooled primers against human IGHV and heavy chain constant region genes, or human IGLV, IGKV, and light chain constant region genes. Cellular barcodes and index adapters (based on Nextera XT Index Adapters, Illumina Inc.) were added using a step-out PCR method. Amplicons were then pooled and sequenced using a 250×250 paired end 8×8 index reads on an Illumina Miseq System. The data were then demultiplexed, heavy and light chain reads were paired, and overlapping sequence reads were obtained (Panda-Seq) (106 (link)) and aligned against the human IMGT database (107 (link)).