“…Uptake was rapid, saturable, and sensitive to competition with unlabeled C3(H 2 O), indicating a specific mechanism of loading. Figure 1A) were generated (14). This distinction between PBCs and their respective cell lines was not limited to B cells, but was true for several other PBCs tested, including CD4 + T cells versus Jurkat, a human T lymphocyte cell line (not shown).…”