New monoclonal anti-human Fc gamma receptor II antibodies induce platelet aggregation.
We developed two new monoclonal antibodies, designated NNKY3-2 and NNKY4-7, that recognized a 40-kD platelet protein. They appeared to be monoclonal anti-Fc gamma receptor II (Fc gamma RII) antibodies from the results of flow cytometric binding inhibition studies using another monoclonal anti-Fc gamma RII antibody (2E1). The addition of NNKY3-2 or NNKY4-7 to platelet-rich plasma (PRP) led to a typical aggregation pattern preceded by a lag phase, but their addition to washed platelets did not induce aggregation. The aggregation of PRP by these antibodies was inhibited by prostaglandin E1 (PGE1) or staurosporine (protein kinase C inhibitor), whereas it was only slightly affected by a monoclonal anti-GPIIb/IIIa antibody or Arg-Gly-Asp-Ser. Furthermore, these antibodies induced the aggregation of washed platelets plus normal serum, but not that of washed platelets plus heat-treated serum (destruction of complement activity). These results suggest that NNKY3-2 or NNKY4-7-induced aggregation involves an unusual pathway independent of fibrinogen, and that the important factor is the participation of complement. NNKY3-2 and NNKY4-7 may be useful to study the relationship between autoantibodies, the Fc receptor, and complement in idiopathic thrombocytopenic purpura.
Nomura
S
S
First Department of Internal Medicine, Kansai Medical University, Osaka, Japan.
Yamaguchi
K
K
Kido
H
H
Kawakatsu
T
T
Iwata
K
K
Fukuroi
T
T
Suzuki
M
M
Yanabu
M
M
Soga
T
T
Nagata
H
H
D000244:Adenosine Diphosphate / Q000378:metabolism; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D000943:Antigens, Differentiation / Q000737:chemistry / Q000276:immunology*; D001241:Aspirin / Q000494:pharmacology; D001792:Blood Platelets / Q000276:immunology*; D015153:Blotting, Western; D000001:Calcimycin / Q000494:pharmacology; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology; D066298:In Vitro Techniques; D008970:Molecular Weight; D010974:Platelet Aggregation / Q000187:drug effects; D011961:Receptors, Fc / Q000737:chemistry / Q000276:immunology*; D017452:Receptors, IgG
D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation; D007075:Immunoglobulin M; D011961:Receptors, Fc; D017452:Receptors, IgG; D000001:Calcimycin; D000244:Adenosine Diphosphate; D001241:Aspirin