APRIL production during macrophage differentiation and exposure to HP or to HP-specific T cells. Monocytes exposed to M-CSF were harvested at the indicated time points and APRIL mRNA was quantified by real-time PCR (A); in parallel the APRIL protein cell content was determined by Western blot. GAPDH was used as marker of equal loading (B). M-CSF–differentiated macrophages (MDM) were exposed to HP (5 × 105 colony-forming unit/mL). At the indicated time points cells were harvested for mRNA evaluation (C) and culture supernatant collected for APRIL content determination (D); AU indicates arbitrary units. In parallel, MDM cytospins were labeled for their intracellular APRIL content (E). HP-specific Th cells isolated from MALT lymphoma patients and from chronic gastritis patients were cocultured with autologous macrophages in the presence of medium or HP antigens and the APRIL production was assessed by ELISA (F). Results represent the APRIL levels induced by T-cell clones over the APRIL production in cultures of macrophages alone. ***P < .01
