A biotech production facility contamination case study--minute mouse virus.

CONFERENCE PROCEEDING Proceedings of the PDA/FDA Adventitious Viruses in Biologics: Detection and Mitigation Strategies Workshop in Bethesda, MD, USA; December 1-3, 2010 Guest Editors: Arifa Khan (Bethesda, MD), Patricia Hughes (Bethesda, MD) and Michael Wiebe (San Francisco, CA).

The role of megakaryocyte growth and development factor in terminal stages of thrombopoiesis.

Thrombopoietin (TPO), the ligand for the c-Mpl cytokine receptor, is a recently identified cytokine with potent effects on platelet production. The receptor-binding portion of c-Mpl ligand is encompassed in another molecule known as megakaryocyte growth and development factor, or MGDF. Although it is clear that the administration of TPO or MGDF to animals dramatically increases the platelet count, the specific stage(s) of thrombopoiesis during which these molecules are principally active have not been unambiguously determined.

Purification and biologic characterization of plasma-derived megakaryocyte growth and development factor.

The isolation and cloning of the ligand for the cytokine receptor, Mpl, have been recently described. In this report we present details of the purification of this novel cytokine (megakaryocyte growth and development factor [MGDF]) from aplastic canine plasma. Two forms of canine MGDF, with apparent molecular weights of 25 kD and 31 kD and sharing a common N-terminal amino acid sequence, were isolated.

Recombinant human megakaryocyte growth and development factor (rHuMGDF), a ligand for c-Mpl, produces functional human platelets in vitro.

Platelet formation, occurring from bone marrow or lung megakaryocytes, has been difficult to study mechanistically. Recombinant human megakaryocyte growth and development factor (rHuMGDF), a recently described cytokine, has now been used to establish an in vitro system in which this important and little understood process occurs. CD34+ cells cultured with rHuMGDF develop into megakaryocytes which form long cytoplasmic extensions (proplatelets) that fragment into platelet-sized particles (in vitro platelets).