Anti-murine CD52 Antibody Treatment Does Not Adversely Affect the Migratory Ability of Immune Cells (P1.222)

OBJECTIVE: To evaluate the migratory properties of various immune cell populations following anti-muCD52 treatment in murine models of inflammation. BACKGROUND: Alemtuzumab is an anti-CD52 humanized monoclonal antibody that causes depletion of circulating lymphocytes followed by a distinctive pattern of repopulation. Alemtuzumab showed superior efficacy vs. subcutaneous interferon beta-1a in phase 3 trials in active relapsing-remitting multiple sclerosis patients who were treatment-naive (CARE-MS I) or had relapsed on prior therapy (CARE-MS II). An anti-muCD52 antibody was utilized to expand our understanding of anti-CD52 therapy in mouse models of immune cell migration. DESIGN/METHODS: Immune cell migration was evaluated using both in vitro and in vivo analysis. Lymphocyte migration in vitro was evaluated in transwell assays using CD4 T cells purified from anti-muCD52-treated mice. In vivo migration was assessed using an acute CNS inflammation model in which mice were injected intracerebroventricularly with lipopolysaccharide (LPS) following anti-muCD52 treatment. Similarly, migration of innate immune cell subsets was evaluated in peritonitis model of inflammation, with animals being injected intraperitoneally with thioglycollate 3 days following anti-muCD52 treatment. The numbers of CNS-infiltrating lymphocytes or peritoneum-infiltrating cells were measured by polychromatic flow cytometry. RESULTS: Immune cells from anti-muCD52-treated mice retained their ability to migrate. In vitro, CD4 T cells were able to migrate in response to SDF-1alpha as efficiently as cells from vehicle-treated animals. In vivo, lymphocytes in anti-muCD52-treated animals were able to migrate into the CNS following local induction of inflammation by LPS. Similarly, innate immune cell migration was not affected by anti-muCD52 treatment, as similar numbers and types of cells were observed in inflamed peritoneum of anti-muCD52- and vehicle-treated animals. CONCLUSIONS: These results indicate that following anti-muCD52 treatment, immune cells retain their ability to migrate. These findings suggest that anti-muCD52 treatment may not compromise immune surveillance, but further studies are required. Study Supported by: Genzyme, a Sanofi company Disclosure: Dr. Havari has received personal compensation for activities with Genzyme Corp. as an employee. Dr. Turner has received personal compensation for activities with Genzyme Corp. as an employee. Dr. Dodge has received personal compensation for activities with Genzyme Corp. as an employee. Mr. Treleaven has received personal compensation for activities with Genzyme Corp. as an employee. Dr. Shihabuddin has received personal compensation for activities with Genzyme Corp. as an employee. Dr. Roberts has received personal compensation for activities with Genzyme Corp. as an employee. Dr. Kaplan has received personal compensation for activities with Genzyme Corp. as an employee. Dr. Siders has received personal compensation for activities with Genzyme, Corp. as an employee.