Quantitation of human in vitro megakaryocytopoiesis by radioimmunoassay
BW Grant, WL Nichols, LA Solberg, DJ Yachimiak and KG Mann
The isolation and characterization of human megakaryocyte growth factors
has been hampered because evaluation of megakaryocyte growth in semisolid
medium requires both lengthy incubation and visual quantitation. In
addition, colony formation requires cell division, while most regulation of
platelet production may involve individual, nonproliferating
differentiating megakaryocytes. We have developed a radioimmunoassay (RIA)
that makes use of an iodinated murine monoclonal antibody (MoAb) specific
for platelet/megakaryocyte glycoprotein IIb/IIIa (GPIIb/IIIa) to measure
megakaryocyte production in liquid marrow culture. This assay is sensitive
to 3 X 10(3) platelets (roughly 30 megakaryocytes) and linear up to 1 X
10(6) platelets, and thus it provides a useful range for quantitating
megakaryocyte production in in vitro marrow culture. Significant
differences (threefold to fivefold) in megakaryocyte/platelet-specific
GPIIb/IIIa complex are detected between stimulated and unstimulated marrow
cultures by day 7, although antigen accrual in stimulated cultures
continues through at least day 16. Conditions that promote megakaryocyte
growth in semisolid medium (ie, aplastic plasma and PHA-LCM) have also been
facilitory in liquid culture. This rapid and sensitive assay for cell-bound
GPIIb/IIIa should facilitate recognition and isolation of megakaryocyte and
platelet growth factors.
Volume 69,
Issue 5,
pp. 1334-1339,
05/01/1987
Copyright © 1987 by The American Society of Hematology
