The relationship of the properties of antihemophilic factor (factor VIII)
that support ristocetin-induced platelet agglutination (factor VIIIR:RC)
and platelet retention by glass beads as demonstrated by a monoclonal
antibody
K Ogata, H Saito and OD Ratnoff
A monoclonal antibody to human antihemophilic factor (AHF, factor VIII) was
derived from BALB/c mouse spleen cells fused with P3x63Ag8 mouse
plasmacytoma cells. This antibody, harvested from culture medium or ascites
fluid, reacted with purified AHF and with plasmas with normal subjects or
classic hemophiliacs, as measured by enzyme-linked immunosorbent assay
(ELISA), but not with plasmas from patients with severe von Willebrand's
disease. The antibody possessed only IgG, heavy chains and kappa light
chains. It blocked ristocetin-induced platelet agglutination and, to a
lesser degree, platelet retention by glass bead columns, but it did not
inhibit the procoagulant activity of AHF significantly. An amount of rabbit
antiserum against AHF that provided equivalent inhibition of
ristocetin-induced platelet agglutination inhibited glass bead retention
much more effectively than the mouse monoclonal antibody. This difference
was exaggerated in studies of the corresponding Fab fragments. These data
suggest that the site or sites on the AHF complex molecule that are
associated with ristocetin-induced platelet agglutination differ
quantitatively or qualitatively from those associated with enhancement of
platelet retention by glass beads. ELISA titers of immunoreactive AHF,
using the monoclonal antibody, were closely correlated to those using
rabbit antiserum against AHF in normal, hemophilic, and most von
Willebrand's disease plasma.
Volume 61,
Issue 1,
pp. 27-35,
01/01/1983
Copyright © 1983 by The American Society of Hematology
