To study the role of anticoagulants, particularly antithrombin III (AT III) and heparin, on the activation of coagulation by monocytes/macrophages which have been stimulated with a soluble lymphocyte activation product, macrophage procoagulant inducing factor, we have prepared monoclonal antibodies (MAbs) to human AT III.In fusion experiments, in contrast to wells containing peritoneal feeder cells, positive hybrids were only found in wells containing medium conditioned by the macrophage cell line J774 (Rathjen and Geczy, 1986). Of 5 hybrids which initially produced antibody, only one hybrid, showed stable Ab production. The MAb, designated 22/23, was not cross-reactive with either 1 antitrypsin or ovalbumin and did not inhibit the biological activity of AT III in chromogenic assays which measured inhibition of thrombin and Factor Xa by AT III. An immunoadsorbent prepared using MAb 22/23 depleted AT III activity from a purified AT III preparation. Reduction and alkylat ion of the disulphide bonds of the protein portion of AT III completely abbrogated MAb binding indicating that the native configuration of AT III was important. Isoelectric focussing of AT III, followed by transfer of the focussed protein to nitrocellulose by diffusion and probing with MAb 22/23, revealed at least 8 bands in the region of pH 5.2 to 5.85. Coomassie blue staining of a gel run in parallel showed 9 bands in this region. The MAb provides a useful tool for the detection of AT III on both cultured cells (bovine aortic endothelial cells are positive by immunofluorescence) and tissue sections.Rathjen, D.A. and Geczy, C.L. Hybridomo. 5s 255-261 (1986)
Heating Greatly Speeds Coomassie Blue Staining and Destaining
