To investigate novel mechanisms and gene programs that support B cell fate decisions after the initial antigen encounter but prior to GC formation, we transferred CD23cre and CD23-Ythdf2-flox/flox TdTomato+ B cells that carry a 4-hydroxy-3-nitrophenyl (NP)-specific B cell receptor (BCR) (B1-8hi) into WT mice, followed by immunization with NP-KLH. A total of three (CD23) and four (CD23-Ythdf2-flox/flox) mice were analysed per genotype. 5 days after immunization and before GC formation, single-cell suspensions from popliteal lymph nodes were labeled with anti-CD45 antibodies linked to cell hashing barcodes, mixed together, and subjected to scRNAseq as a single pooled sample.