library_construction_protocol: Apex-binding B cells were isolated from lymph node and peripheral blood samples collected from rhesus macaques immunized with the Apex-GT6 immunogen. Two groups of animals were used: one group received 100 µg of soluble Apex-GT6 protein formulated with the SMNP adjuvant, and the other received membrane-bound Apex-GT6 protein. Fine needle aspirates (FNAs) were collected from lymph nodes at weeks 2, 4, 8, and 12 post-immunization to isolate germinal center (GC) B cells. Peripheral blood mononuclear cells (PBMCs) were collected at week 10 for both mRNA and protein analysis, and again at week 17 for protein analysis only. To identify Apex-binding B cells, samples were stained with tetramerized Apex-GT6 probes conjugated to fluorescent streptavidin (SA) and TotalSeq-C oligo-tagged SA. Surface staining included a panel of fluorescently labeled antibodies, along with one of ten different TotalSeq-C oligo-tagged antibodies per sample. These oligo-tagged antibodies targeted β2M and CD298 and served as sample-specific hashtags to enable multiplexing across animals. Cells were sorted on a FACSymphony S6 (BD Biosciences). Apex-binding GC and memory B cells were collected into 1.5 mL tubes containing RPMI 1640 medium supplemented with 50% fetal bovine serum (FBS) and kept on ice for immediate downstream processing. Lymph Node Libraries were constructed according to the manufacturer's protocol using the Chromium Next GEM Single Cell 5' Reagent Kit v1.1. Lymph Node Libraries were constructed according to the manufacturer's protocol using the Chromium Next GEM Single Cell 5' Reagent Kit v2