Fig. 4: Antibody-induced complement activation leads to mitochondrial actin downregulation, impacting CDC.

A Western blot analysis of actin in (C) cytosolic and (M) mitochondrial-enriched fractions in U2932-WT and U2932-R cells, at baseline and upon DuoHexaBody-CD37-induced (1 µg/mL) CDC. Tubulin is shown as cytosolic loading control. Representative blot shown (n = 3). B–D Quantification of actin band intensity normalized to cytosolic tubulin and expressed relative to cytosolic U2932-WT (set to 1). Shown are baseline levels (left), post-CDC levels in U2932-WT (middle), and post-CDC levels in U2932-R (right). E Cytotoxicity (%) achieved by DuoHexaBody-CD37 1 µg/mL (left) or 10 µg/mL (right) in U2932-WT in conventional CDC assays with or without 1-h jasplakinolide (8 µM) pre-treatmen (n ≥ 3). F Cytotoxicity (%) achieved by DuoHexaBody-CD37 (10 µg/mL) in U2932-R in conventional CDC assays with or without 1-h jasplakinolide (8 µM) pre-treatment (n ≥ 3). G Cytotoxicity (%) achieved by rituximab (RTX; 10 µg/mL) in LY18 (left) and LY1 (right) with or without a 30-min Cytochalasin D (5 µM) treatment (n ≥ 3). N indicates independent experiments, each performed in replicate or as triplicates; the average value per experiment was used for analysis. Data are shown as mean ± SD and statistical analyses were performed using one-way ANOVA with post-hoc Tukey’s multiple comparison test.