Abstract:

BACKGROUND: There have been no reports regarding the precise FXIII binding epitopes for blood coagulation factor XIII (FXIII) acting on FXIII inhibitor.
OBJECTIVE: To prepare rabbit polyclonal antibody against human FXIII A subunit by immunologic method, and to identify antibody specificity and activity.
METHODS: The polyclonal antibody was prepared by immunizing rabbits using artificially synthesized FXIIIA subunit. Antibody specificity was identified by Dot blot method, and antibody activity was determined by antibody-neutralizing/ urea-lysis test. Serum level of FXIII in two patients with acquired FXIII deficiency was determined by western blot assay. The FXIII binding epitopes of these two patients were analyzed by Dot blot method.
RESULTS AND CONCLUSION: Dot blot results showed that the polyclonal antibody against FXIII A subunit had already been produced in rabbit serum. The antibody not only binded to purified human FXIII and transglutaminase active site, but also inhibited the activity of FXIII in vitro. The FXIII antigen level in two patients with acquired FXIII deficiency could be detected using this antibody and active site of transglutaminase on FXIII was the binding epitope of FXIII inhibitor in case 2, but not in case 1. The successful preparation of polyclonal antibody, which is applied to detect FXIII deficiency and determine FXIII binding epitopes, provides basis for studying the mechanism of acquired FXIII deficiency and clinical diagnosis.