Panel A: A flowchart illustrates naïve B-cell stimulation with interleukin-4 and 40LB cells, formation of iGCB cells, ovalbumin peptide 323–339 loading, co-culture with CellTrace Violet-labeled OT-II cluster of differentiation 4-positive T cells, and proliferation analysis using fluorescence-activated cell sorting. Panel B: Upper flow-cytometry plots show OT-II cluster of differentiation 4-positive T-cell proliferation under different blocking-antibody conditions, while lower bar graphs summarize proliferation percentages and statistical significance between experimental groups. Panel C: A graphical abstract depicts eukaryotic translation initiation factor 3 subunit E deficiency in B cells increasing cluster of differentiation 80 expression, promoting feedforward T-cell and B-cell interactions, aberrant lymphocyte activation, proliferation, and malignant transformation.
CD80 upregulation by Eif3e-deficient B cells drives antigen-dependent CD4 + T cell activation. (A) Experimental outline for B–T cell coculture. Naïve OT-II CD4+ T cells labeled with CellTrace Violet were cocultured with OVA peptide 323–339–loaded iGCBs for 2.5 days. Proliferation of OT-II CD4+ T cells was measured by flow cytometry. (B) Upper panels: Representative FACS plots showing proliferation of OT-II CD4+ T cells cocultured with cKO or control iGCBs under indicated conditions. Below: Bar graphs summarizing proliferation of CD4+ T cells. Statistical analysis was performed using paired two-tailed Student’s t test. ns, not significant, P > 0.05; *P < 0.05; **P < 0.01; ****P < 0.0001. Three independent experiments (B) were performed. (C) Graphical abstract. Eif3e deficiency in B cells leads to elevated expression of CD80, a feedforward loop of T–B interaction, and aberrant activation and proliferation of B and CD4+ T cells, which culminate in malignant transformation of eIF3e-sufficient B or T cells.