RRC ID 67770
Author Tanizaki Y, Ishida-Iwata T, Obuchi-Shimoji M, Kato T.
Title Cellular characterization of thrombocytes in Xenopus laevis with specific monoclonal antibodies.
Journal Exp Hematol
Abstract Platelets are produced from megakaryocytes (MKs) in the bone marrow. In contrast, most nonmammalian vertebrates have nucleated and spindle-shaped thrombocytes instead of platelets in their circulatory systems, and the presence of MKs as thrombocyte progenitors has not been verified. In developing a new animal model in adult African clawed frog (Xenopus laevis), we needed to distinguish nucleated thrombocytes and their progenitors from other blood cells, because the cellular morphology of activated thrombocytes resembles lymphocytes and other cells. We initially generated two monoclonal antibodies, T5 and T12, to X. laevis thrombocytes. Whereas T5 recognized both thrombocytes and leukocytes, T12 specifically reacted to spindle-shaped thrombocytes. The T12(+) thrombocytes displayed much higher DNA ploidy than nucleated erythrocytes, and they expressed CD41 and Fli-1. In the presence of CaCl2, adenosine diphosphate, thrombin, or various collagens, T12(+) thrombocytes exhibited aggregation. These thrombocytes were located predominantly in the hepatic sinusoids and the splenic red pulp, suggesting that both organs are the sites of thrombopoiesis. Notably, circulating thrombocytes exhibited lower DNA ploidy than hepatic thrombocytes. Intraperitoneal administration of T12 produced immune thrombocytopenia in frogs, which reached a nadir 4 days postinjection, followed by recovery, suggesting that humoral regulation maintained the number of circulating thrombocytes. Although differences between MKs and thrombocytes in X. laevis remain to be defined, our results provide further insight into MK development and thrombopoiesis in vertebrates.
Volume 43(2)
Pages 125-36
Published 2015-2-1
DOI 10.1016/j.exphem.2014.10.005
PII S0301-472X(14)00711-5
PMID 25448492
MeSH Adenosine Diphosphate / pharmacology Animals Antibodies, Monoclonal / biosynthesis Antibodies, Monoclonal / pharmacology* Biomarkers / metabolism Blood Platelets / cytology* Blood Platelets / drug effects Blood Platelets / immunology Calcium Chloride / pharmacology Cells, Cultured Collagen / pharmacology Gene Expression Liver / cytology* Liver / drug effects Liver / immunology Lymphocytes / cytology Lymphocytes / drug effects Lymphocytes / immunology Male Mice Mice, Inbred BALB C Organ Specificity Platelet Aggregation Platelet Membrane Glycoprotein IIb / genetics Platelet Membrane Glycoprotein IIb / immunology Ploidies Proto-Oncogene Protein c-fli-1 / genetics Proto-Oncogene Protein c-fli-1 / immunology Spleen / cytology* Spleen / drug effects Spleen / immunology Thrombin / pharmacology Thrombocytopenia / chemically induced Thrombocytopenia / immunology Thrombocytopenia / pathology Thrombopoiesis Xenopus laevis / genetics Xenopus laevis / immunology
IF 2.82
Human and Animal Cells SP2/0-Ag14(RCB0209)