Tolerance to factor VIII in a transgenic mouse expressing human factor VIII cDNA carrying an Arg(593) to Cys substitution.
Inhibitory antibodies develop in approximately 25% of patients with severe hemophilia. A following treatment with factorVIII. In E-16KO or E-17KO mice, in which the factor VIII gene has been inactivated by insertion of a neo cassette, inhibitors develop following administration of factor VIII. Here, we describe the generation of transgenic mice expressing human factor VIII-R593C (huFVIII-R593C). Human factor VIII-R593C cDNA under control of a mouse albumin enhancer/promoter was injected into fertilized oocytes. Analysis of transgenic mice revealed that human factor VIII-R593C was expressed in the liver. Transgenic mice were crossed with factor VIII-deficient mice (E-16KO mice). In plasma of E-16KO mice antibodies were detected after five serial intravenous injections of factor VIII, while plasma of huFVIII-R593C/E-16KO mice did not contain detectable levels of antibodies. No antibody secreting cells were observed in either spleen or bone marrow of huFVIII-R593C/E-16KO mice. Also, factor VIII-specific memory B cells were not observed in the spleen of huFVIII-R593C/E-16KO mice. Analysis of T cell responses revealed that splenocytes derived of E-16KO mice secreted IL-10 and IFN-gamma following restimulation with factor VIII in vitro. In contrast, no factor VIII-specific T cell responses were observed in huFVIII-R593C/E-16KO mice. These results indicate that huFVIII-R593C/E-16KO mice are tolerant to intravenously administered factor VIII. It is anticipated that this model may prove useful for studying immune responses in the context of factor VIII gene therapy.
Department of Plasma Proteins, Sanquin Research at CLB, Plesmanlaan 125, 1066 CX Amsterdam, The Netherlands.
Wendy S
WS
Bril
Pauline M W
PM
van Helden
Christina
C
Hausl
Marleen G
MG
Zuurveld
Rafi U
RU
Ahmad
Martine J
MJ
Hollestelle
Pieter H
PH
Reitsma
Karin
K
Fijnvandraat
Rene A W
RA
van Lier
Hans Peter
HP
Schwarz
Koen
K
Mertens
Birgit M
BM
Reipert
Jan
J
Voorberg
D019943:Amino Acid Substitution; D000818:Animals; D001120:Arginine; D003545:Cysteine; D018076:DNA, Complementary; D005169:Factor VIII / Q000008:administration & dosage / Q000235:genetics* / Q000276:immunology; D006801:Humans; D007108:Immune Tolerance / Q000235:genetics*; D007518:Isoantibodies / Q000097:blood*; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D023421:Models, Animal
D018076:DNA, Complementary; D007518:Isoantibodies; D005169:Factor VIII; D001120:Arginine; D003545:Cysteine