A novel flow cytometric based in vivo ADCC assay for screening lytic murine antibodies (50.42)

• Published in: The Journal of immunology (1950) Vol. 182; no. 1_Supplement; pp. 50 - 50.42
• Main Authors: Evans, Lawrence S, Butz, Eric A
• Format: Journal Article
• Language: English
• Published: 01.04.2009
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.182.Supp.50.42

Abstract CD70 is a TNF superfamily member that is not normally expressed on resting cells, but is induced on lymphocytes and dendritic cells upon activation. Aberrant upregulation of CD70 is observed in several human autoimmune diseases, including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and graft versus host disease (GVHD). Therefore, depletion of CD70+ cells could have a significant impact in these diseases and in animal models where CD70+ cells play a prominent role. Though in vitro antibody-dependent cell-mediated cytotoxicity (ADCC) assays perform well with human cells they are difficult to do using mouse effectors and targets. We have developed an in vivo ADCC assay using carboxyfluorescein succinimidyl ester (CFSE) labeled target cells that allows us to measure in vivo target depletion in the presence of anti-CD70 antibodies. The antibodies tested displayed differential lytic capacities in vivo that were not evident from in vitro ADCC assays. The relative roles of NK cells, FcγIII/II Receptor (CD16/CD32), and complement on in vivo depletion have also been examined. We believe that this assay is a useful tool in examining the lytic activities of mouse Ab that have been difficult to determine using in vitro assays.