title: In vivo efficacy of anti-MPL agonist antibody in promoting primary human hematopoietic cells.
abstract: In a previous study, we generated novel antithrombopoietin receptor agonist antibodies as therapeutic candidates. In this report, we investigated the in vivo effects of one of these antibodies, MA01G4344U, on primary human hematopoietic cells using xenotransplantation. NOD/Shi-scid, IL-2Rgamma(null) (NOG) mice were pretreated by total-body irradiation and received a transplant of human cord blood-derived CD34(+) cells. Weekly intraperitoneal injection of MA01G4344U (100 microg/mouse per week) or Peg-rhMGDF (5 microg/mouse per week) or phosphate-buffered saline (PBS) was performed. Human cells in peripheral blood were analyzed by flow cytometry and bone marrow cells were analyzed by flow cytometry and colony assay. MA01G4344U successfully increased the number of human CD41(+) platelets and human CD45(+) cells in peripheral blood. In the bone marrow, MA01G4344U increased the number of human CD45(+)/CD34(+) cells, which resulted in more multilineage progenitor cells. The efficacy of MA01G4344U in promoting primary human hematopoietic cells in vivo suggests its therapeutic potential for thrombocytopenic and pancytopenic disorders.
authors.affiliation: Innovative Drug Research Laboratories, Research Division, Kyowa Hakko Kirin Co Ltd, Takasaki, Japan. masayuki.kai@kyowakirin.co.jp
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kai
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Hagiwara
authors.forename: Chie
authors.initials: C
authors.lastname: Emuta
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Chisaka
authors.forename: Kumi
authors.initials: K
authors.lastname: Tsuruhata
authors.forename: Chisato
authors.initials: C
authors.lastname: Endo
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Inagaki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Miyazaki
authors.forename: Shiro
authors.initials: S
authors.lastname: Kataoka
mesh_terms: D000818:Animals; D000906:Antibodies / Q000494:pharmacology*; D018952:Antigens, CD34 / Q000378:metabolism; D001773:Blood Cells / Q000187:drug effects* / Q000378:metabolism; D001854:Bone Marrow Cells / Q000187:drug effects* / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008297:Male; D051379:Mice; D040201:Platelet Membrane Glycoprotein IIb / Q000378:metabolism; D053628:Receptors, Thrombopoietin / Q000819:agonists* / Q000276:immunology
chemical_list: D000906:Antibodies; D018952:Antigens, CD34; D040201:Platelet Membrane Glycoprotein IIb; D053628:Receptors, Thrombopoietin; C082218:MPL protein, human; D017493:Leukocyte Common Antigens