| Research Abstract |
1.Factor VIII expression : Recombinant adeno viral vector consisting of Cytomegalovirus enhancer/chiken _-actin promoter/rabbit _-globulin 3'UTR, B domain less canine factor VIII gene and rabbit _-globulin poly A was constructed. COS1, HepG2 and Hela cells were transfected and FVIII was expressed. Approximately 0.6 unit/ml and 1.0 unit/ml of factor VIII was detected by COS1 cells at day 4 and 7, respectively. Furthermore, 0.8 unit/ml of and 1.0unit/ml of factor VIII was detected by HepG2 cells at day 4 and day 7, respectively. Factor VIII was not detected by Hela cells.
2.Immunological influence : Immunological and biological characterizations of anti-factor VIII alloantibodies were analyzed. Especially, (1)IgG subclass specificity, (2)binding region of the alloantibodies, (3)inhibitory mechanism on factor VIII cofactor function were determined. We demonstrated for the first time the inhibitory effects on factor IX binding, factor VIII binding to von Willebrand factor and activated platelets and inhibitory effects on factor VIII activation by thrombin and activated factor Xa. Furthermore, we detected factor VIII/anti-factor VIII autoantibodies immune complex in plasma.
3.Interaction between factor VIII genotype of heamophilia A patient and development of anti-factor VIII alloantibodies : We found a close relationship between HLA-DR4.1, DQ4 and DQA1 and inhibitor development. Furthermore we also found that some factor VIII genotype was associated with the development of inhibitor.
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