IgG+ expressing B-cells are depleted by anti-human IgG STALs even in the presence of soluble IgG antibody. a) Human memory B-cells were isolated from healthy control PBMCs and incubated under one of the following conditions: unstimulated (PBS), anti-human IgG-liposomes (αIgG Lip), anti-human IgG+hCD22L (αIgG STALs), or CD22L liposomes alone (CD22L Lip) for 24 hrs. After 24hrs, cells were stained for markers of activation (CD69) and cell death (Annexin V/PI) (N=10 for PBS, αIgG, and αIgG STAL, N=7 for CD22L Lip, each independent experiments, pooled data, one-way ANOVA with multiple comparisons). c) B-cells were cultured under the same conditions as above, except that soluble IgG (5 ng/mL) was added to the wells prior to the addition of PBS or the liposomes (N=4 for PBS, αIgG, αIgG STALS, and CD22L Lip, each an independent experiment, pooled data, one-way ANOVA with multiple comparisons). Representative FACS analysis data on activation marker CD69 and cell death markers annexin V and PI uptake from one healthy donor are shown.