Investigation of Lymphocyte Depletion and Repopulation Using Alemtuzumab (Campath‐1H) in Cynomolgus Monkeys

• Published in: American journal of transplantation Vol. 10; no. 4; pp. 773 - 783
• Main Authors: Van Der Windt, D. J., Smetanka, C., Macedo, C., He, J., Lakomy, R., Bottino, R., Ekser, B., Echeverri, G. J., Metes, D., Ijzermans, J. N. M., Trucco, M., Cooper, D. K. C., Lakkis, F. G.
• Format: Journal Article
• Language: English
• Published: Malden, USA Blackwell Publishing Inc 01.04.2010; Wiley; Elsevier Limited
• Subjects: Agglutination; Alemtuzumab; Animal models; Animals; Antibodies, Monoclonal - pharmacology; Antibodies, Monoclonal - therapeutic use; Antibodies, Monoclonal, Humanized; Antibodies, Neoplasm - pharmacology; Antibodies, Neoplasm - therapeutic use; Antigens, CD - immunology; Antilymphocyte serum; Biological and medical sciences; Campath‐1H; CD20 antigen; CD4 antigen; CD8 antigen; Cell Division - drug effects; Cell proliferation; Cynomolgus; Dosage; Effector cells; Erythrocytes; Flow Cytometry; Globulins; Immunophenotyping; Lymph nodes; Lymphocyte Depletion; Lymphocytes; Lymphocytes - cytology; Lymphocytes - immunology; Lymphocytes B; Lymphocytes T; Macaca fascicularis; Medical sciences; Memory cells; monkey; Monkeys & apes; Monoclonal antibodies; Mycophenolate mofetil; Mycophenolic acid; nonhuman primate; Primates; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Thymocytes; Transplantation; Antineoplastic agent; Flow cytometry; Nonhuman primate; Monkey; Campath-1H; Alemtuzumab; Monoclonal antibody; Immunomodulator; cynomolgus; Vertebrata; Mammalia; Depletion; Treatment; Animal; Immunotherapy; Primates; Immunosuppressive agent; Lymphocyte
• ISSN: 1600-6135; 1600-6143
• DOI: 10.1111/j.1600-6143.2010.03050.x

As the target CD52 molecule is expressed on erythrocytes of most nonhuman primate strains, using alemtuzumab in these species would cause massive hemolysis. Six cynomolgus monkeys of Indonesian origin, screened by agglutination assay for absence of CD52 on erythrocytes, were administered alemtuzumab in a cumulative dose to a maximum of 60 mg/kg. In two monkeys, mycophenolate mofetil (MMF) was added as maintenance therapy. Complete depletion of T and B lymphocytes (>99.5%) was achieved with 20 mg/kg alemtuzumab and was more profound than in monkeys treated with antithymocyte globulin (n = 5), as quantified by flow cytometry. Repopulation was suppressed by weekly injections of 10 mg/kg. Without MMF, repopulation of CD20+B cells and CD8+T cells was complete within 2 and 3 months, respectively, and repopulation of CD4+T cells was 67% after 1 year. MMF significantly delayed CD4+T‐cell repopulation. Among repopulating CD4+ and CD8+ T cells, a phenotypic shift was observed from CD45RAhiCD62Lhi naïve cells toward CD45RAloCD62Llo effector memory cells. In lymph nodes, the depletion of naïve cells was more profound than of memory cells, which may have initiated a proliferation of memory cells. This model offers opportunities to investigate lymphocyte depletion/repopulation phenomena, as well as the efficacy of alemtuzumab in preclinical transplantation models. Alemtuzumab administered to nonhuman primates that are negative for CD52 on erythrocytes achieves excellent lymphocyte depletion while avoiding hemolysis.