Technetium-99m labeled 50H.19 antibody fragments: interaction of the antibody with platelets.
The monoclonal antibody 50H.19 recognized three antigens (Mr = 31-, 40-, 45-K) on normal and thromboasthenic platelets, but only one (Mr = 31-K) on Bernard-Soulier platelets. The intact antibody and its F(ab')2 fragments, had direct platelet-aggregating activity, and induced the platelet release reaction. The intact antibody potentiated platelet aggregation induced by platelet-activating factor or thrombin. Additions of indomethacin did not inhibit aggregation: addition of PGI2, or a calcium channel blocker completely inhibited aggregation. A reduced amount of platelet-aggregating activity was observed with antibody fragments prepared for labeling with 99mTc by pre-exposure to stannous ions, and herein used in biodistribution studies and elsewhere in thrombus imagining studies (J. Nucl. Med. 27: 1315; 1986). Antibody fragments radiolabeled with 99mTc bound to isolated platelets and to clots containing platelets.
Valone
F H
FH
University of California, San Francisco, Veterans Administration Medical Center 94121.
Stricker
R B
RB
Zamora
P O
PO
Shah
V O
VO
Mann
P L
PL
D000911:Antibodies, Monoclonal / Q000276:immunology*; D000941:Antigens / Q000032:analysis; D001606:Bernard-Soulier Syndrome / Q000097:blood; D001792:Blood Platelets / Q000276:immunology*; D006801:Humans; D007128:Immunoglobulin Fragments / Q000276:immunology; D066298:In Vitro Techniques; D010974:Platelet Aggregation; D013667:Technetium; D013915:Thrombasthenia / Q000097:blood; D014018:Tissue Distribution
D000911:Antibodies, Monoclonal; D000941:Antigens; D007128:Immunoglobulin Fragments; D013667:Technetium