Effect of MALT1 and API2-MALT1 on NF-κB activation as measured by CD83 expression. FACS measurement of surface markers in BJAB lines with no transgene (dotted line), MALT1 (thin line), or API2-MALT1 (bold line) secondarily infected with empty vector (top panels) or IκBα superrepressor (bottom panels). Histograms show CD83 expression after 4 hour incubation with cross-linked CD40L (A), PMA+ionomycin (B), or medium alone (C). Histogram (D) shows resting CD40 expression in the 6 lines.