Detects human Tpo in direct ELISAs and Western blots. In direct ELISAs, less than 10% cross-reactivity with recombinant mouse Tpo and recombinant rat Tpo is observed.
Polyclonal Goat IgG
S. frugiperda insect ovarian cell line Sf 21-derived recombinant human Tpo Ser22-Gly353 Accession # P40225
Lyophilized from a 0.2 μm filtered solution in PBS with Trehalose. *Small pack size (SP) is supplied as a 0.2 µm filtered solution in PBS.
<0.10 EU per 1 μg of the antibody by the LAL method.
Recombinant Human Thrombopoietin/Tpo (Catalog # 288-TP)
Measured by its ability to neutralize Thrombopoietin/Tpo-induced proliferation in the MO7e human megakaryocytic leukemic cell line. Avanzi, G. et al. (1988) Br. J. Haematol. 69:359. The Neutralization Dose (ND50) is typically 0.05-0.3 µg/mL in the presence of 3 ng/mL Recombinant Human Thrombopoietin/Tpo.
Please Note: Optimal dilutions should be determined by each laboratory for each application. General Protocols are available in the Technical Information section on our website.
Cell Proliferation Induced by Thrombopoietin and Neutralization by Human Thrombopoietin Antibody. Recombinant Human Thrombopoietin/Tpo (Catalog # 288-TP) stimulates proliferation in the MO7e human megakaryocytic leukemic cell line in a dose-dependent manner (orange line). Proliferation elicited by Recombinant Human Thrombopoietin/Tpo (3 ng/mL) is neutralized (green line) by increasing concentrations of Human Thrombopoietin/Tpo Antigen Affinity-purified Polyclonal Antibody (Catalog # AF-288-NA). The ND50 is typically 0.05-0.3 µg/mL.
Preparation and Storage
Reconstitute at 0.2 mg/mL in sterile PBS.
The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below. *Small pack size (SP) is shipped with polar packs. Upon receipt, store it immediately at -20 to -70 °C
Stability & Storage
Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
12 months from date of receipt, -20 to -70 °C as supplied.
1 month, 2 to 8 °C under sterile conditions after reconstitution.
6 months, -20 to -70 °C under sterile conditions after reconstitution.
Thrombopoietin (Tpo), is a key regulator of megakaryocytopoiesis and thrombopoiesis. It is principally produced in the liver and is bound and internalized by the receptor Tpo R/c-mpl. Defects in the Tpo-Tpo R signaling pathway are associated with a variety of platelet disorders (1 - 3). The 353 amino acid (aa) human Tpo precursor is cleaved to yield the 332 aa mature protein. Mature human Tpo shares approximately 70% aa sequence homology with mouse and rat Tpo. It is an 80 - 85 kDa protein that consists of an N-terminal domain with homology to Erythropoietin (Epo) and a C-terminal domain that contains multiple N-linked and O-linked glycosylation sites (4, 5). Tissue specific alternate splicing of human Tpo generates multiple isoforms with internal deletions, insertions, and/or C-terminal substitutions (6). Tpo promotes the differentiation, proliferation, and maturation of MK and their progenitors (4, 5, 7). Several other cytokines can promote these functions as well but only in cooperation with Tpo (8, 9). Notably, IL-3 independently induces MK development, although its effects are restricted to early in the MK lineage (8, 9). Tpo additionally promotes platelet production, aggregation, ECM adhesion, and activation (10, 13). It is cleaved by platelet-derived thrombin following Arg191 within the C-terminal domain and subsequently at other sites upon extended digestion (14). Full length Tpo and shorter forms circulate in the plasma (4, 5). TheC-terminal domain is not required for binding to Tpo R or inducing MK growth and differentiation (5). Aside from its hematopoietic effects, Tpo is expressed in the brain where it promotes the apoptosis of hypoxia-sensitized neurons and inhibits neuronal differentiation by blocking NGF induced signaling (15, 16).
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