Abstract 17353: B Cell Depletion Promotes Aortic Infiltration of Tolerogenic Immune Cells and is Protective of Experimental Aortic Aneurysm

Anti-CD20 antibody-mediated B cell depletion therapy is widely used for the treatment of B cell malignancies and rheumatoid arthritis. Given the observation that B cells are abundant in abdominal aortic aneurysms (AA), we hypothesize that B cell depletion would be protective of experimental AA formation. C57BL/6j and IL-10 knock-out (KO) mice (male, 8-10 weeks old) were injected intraperitoneal (IP) or intravenous (IV) with mouse monoclonal anti-CD20 IgG2a (or IgG2a control) antibodies at day 7 before and day 7 following induction of AA using the elastase AA perfusion model. AA size was measured at day 14 following perfusion. Depletion of B cell (B1, B2 and IL-10 producing B cells) was confirmed using flow cytometry or immunohistochemistry. IgG and IgM levels were quantified using ELISA. One-way ANOVA was used for data analysis. B1 cells were prominent in peritoneal cavity, whereas B2 cells were spleen and blood. 85-95% of B1 and B2 cells were depleted at day 7 following both IP and IV treatments. Interes...