scholarly journals The diversity of the immune response to the A2 domain of human factor VIII

Blood ◽  
2013 ◽  
Vol 121 (14) ◽  
pp. 2785-2795 ◽  
Author(s):  
Rebecca C. Markovitz ◽  
John F. Healey ◽  
Ernest T. Parker ◽  
Shannon L. Meeks ◽  
Pete Lollar
Keyword(s):  
Immune Response ◽  
Factor Viii ◽  
Human Factor ◽  
Hemophilia A ◽  
Entire Surface ◽  
Human Factor Viii ◽  
Key Points ◽  
A2 Domain

Key Points The Abs to the human fVIII A2 domain in a murine hemophilia A model inhibit fVIIIa and activation of fVIII Epitopes targeted by hemophilia A mouse Abs cover nearly the entire surface of the human fVIII A2 domain

Mechanism of the Immune Response to Human Factor VIII in Murine Hemophilia A

2001 ◽  
Vol 85 (01) ◽  
pp. 125-133 ◽  
Author(s):  
Huiyun Wu ◽  
Mark Reding ◽  
Jiahua Qian ◽  
David Okita ◽  
Ernie Parker ◽  
...  
Keyword(s):  
Immune Response ◽  
Factor Viii ◽  
Human Factor ◽  
Hemophilia A ◽  
Th2 Cells ◽  
Tween 20 ◽  
Sorbitan Monolaurate ◽  
Human Factor Viii ◽  
Ifn Γ ◽  
Th1 And Th2

SummaryMice genetically deficient in factor VIII (fVIII) are a model of hemophilia A. As a first step to reproduce in this mouse model what occurs over time in hemophilia A patients treated with human fVIII (hfVIII), we have investigated the time course and the characteristics of their immune response to hfVIII, after multiple intravenous injections. Anti-hfVIII antibodies appeared after four to five injections. They were IgG1 and to a lesser extent IgG2, indicating that they were induced by both Th2 and Th1 cells. Inhibitors appeared after six injections. CD4+ enriched splenocytes from hfVIII-treated mice proliferated in response to fVIII and secreted IL-10: in a few mice they secreted also IFN-γ and in one mouse IL-4, but never IL-2. A hfVIII-specific T cell line derived from hfVIII-treated mice secreted both IL-4 and IFN-γ, suggesting that it included both Th1 and Th2 cells. CD4+ enriched splenocytes of hfVIII-treated mice recognized all hfVIII domains. Thus, hemophilic mice develop an immune response to hfVIII administered intravenously similar to that of hemophilia A patients. Their anti-hfVIII antibodies can be inhibitors and belong to IgG subclasses homologous to those of inhibitors in hemophilic patients; their anti-hfVIII CD4+ cells recognize a complex repertoire and both Th1 and Th2 cytokines, and especially IL-10, may drive the antibody synthesis. Abbreviations used: antibodies, Ab; antigen presenting cells, APC; Arbitrary Units, AU; enzyme-linked immunosorbant assay, ELISA; factor VIII, fVIII; human factor VIII, hf VIII; intravenous, i.v.; optical density, OD; polymerase chain reaction, PCR; phosphate buffered saline solution, PBS; PBS containing 3% bovine serum albumin, PBS/BSA; PBS containing 0.05% polyoxyethylene sorbitan monolaurate, PBS/Tween-20; phytohemoagglutinin, PHA; stimulation index, SI

Inhibitor Antibody Development and T Cell Response to Human Factor VIII in Murine Hemophilia A

1999 ◽  
Vol 81 (02) ◽  
pp. 240-244 ◽  
Author(s):  
Jiahua Qian ◽  
Marina Borovok ◽  
Lei Bi ◽  
Haig Kazazian ◽  
Leon Hoyer
Keyword(s):  
Immune Response ◽  
T Cell ◽  
Factor Viii ◽  
Proliferative Response ◽  
Human Factor ◽  
Hemophilia A ◽  
Single Injection ◽  
T Cell Response ◽  
Cell Proliferative Response ◽  
Human Factor Viii

SummaryIn order to understand better the mechanism of inhibitor formation in hemophilia A patients, we have characterized the immune response to human factor VIII in a murine model of hemophilia A. Mice with severe factor VIII deficiency caused by targeted gene disruptions in exons 16 and 17 were injected intravenously with human factor VIII. Anti-factor VIII was absent or was detected at only very low levels in hemophilic mice of both strains after a single injection of 0.2 μg factor VIII, but it was present in most mice after a second exposure. Subsequent exposures led to high titer anti-factor VIII antibodies in both ELISA and inhibitor assays. A human factor VIII-specific T cell proliferative response was detected with spleen cells obtained three days after a single injection with human factor VIII, before mice had detectable anti-factor VIII antibodies. Subsequent exposures to factor VIII were followed by an increased T cell proliferative response. These studies indicate that murine hemophilia A is a good model for the study of the immune response to human factor VIII, especially the role of the T cell in the early steps in inhibitor antibody formation.

scholarly journals Therapeutic levels of FVIII following a single peripheral vein administration of rAAV vector encoding a novel human factor VIII variant

Blood ◽  
2013 ◽  
Vol 121 (17) ◽  
pp. 3335-3344 ◽  
Author(s):  
Jenny McIntosh ◽  
Peter J. Lenting ◽  
Cecilia Rosales ◽  
Doyoung Lee ◽  
Samira Rabbanian ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Factor Viii ◽  
Nonhuman Primates ◽  
Human Factor ◽  
Hemophilia A ◽  
Raav Vector ◽  
Peripheral Vein ◽  
Human Factor Viii ◽  
Key Points

Key Points Novel, more potent codon-optimized human FVIII variant (codop-hFVIII-V3). Codop-hFVIII-V3 is safe and efficacious in mice and nonhuman primates, thus improving the prospects of gene therapy for hemophilia A.

Identification of a Novel Missense Mutation in Exon 4 of the Human Factor VIII Gene Associated with Sever Hemophilia a Patient

2007 ◽  
Vol 10 (23) ◽  
pp. 4299-4302 ◽  
Author(s):  
Habib Onsori ◽  
Mohammad Ali Hossein . ◽  
Sheideh Montaser-Kou . ◽  
Mohammad Asgharzadeh . ◽  
Abbas Ali Hosseinpou .
Keyword(s):  
Factor Viii ◽  
Missense Mutation ◽  
Human Factor ◽  
Hemophilia A ◽  
Factor Viii Gene ◽  
Human Factor Viii ◽  
Exon 4

scholarly journals Sustained expression of therapeutic levels of human factor VIII in mice

Blood ◽  
1996 ◽  
Vol 87 (11) ◽  
pp. 4671-4677 ◽  
Author(s):  
S Connelly ◽  
JM Gardner ◽  
RM Lyons ◽  
A McClelland ◽  
M Kaleko
Keyword(s):  
Factor Viii ◽  
Adenoviral Vector ◽  
Human Factor ◽  
Hemophilia A ◽  
Coagulation Factor ◽  
High Dose ◽  
Specific Enzyme ◽  
Adult Mice ◽  
Human Factor Viii

Deficiency of coagulation factor VIII (FVIII) results in hemophilia A, a common hereditary bleeding disorder. Using a human FVIII-encoding adenoviral vector, Av1ALAPH81, we have demonstrated expression of therapeutic levels of human FVIII in mice sustained for more than 5 months after vector administration. Administration of a high dose (4 x 10(9) plaque-forming units [pfu]) of Av1ALAPH81 to mice resulted in a peak expression of 2,063 ng/mL of human FVIII in the mouse plasma, with levels decreasing to background by weeks 15 to 17. Normal FVIII levels in humans range from 100 to 200 ng/mL and therapeutic levels are as low as 10 ng/mL. Alternatively, administration of 8- to 80-fold lower vector doses (5 x 10(8) pfu to 5 x 10(7) pfu) to normal adult mice resulted in expression of FVIII at therapeutic levels sustained for at least 22 weeks. Detailed analysis of vector toxicity indicated that the high vector dose caused a dramatic elevation of liver-specific enzyme levels, whereas an eight-fold lower vector dose was significantly less hepatotoxic. The data presented here demonstrate that administration of lower, less toxic vector doses allow long-term persistence of FVIII expression.

Localization of epitopes for human factor VIII inhibitor antibodies by immunoblotting and antibody neutralization

Blood ◽  
1989 ◽  
Vol 74 (5) ◽  
pp. 1618-1626 ◽  
Author(s):  
D Scandella ◽  
M Mattingly ◽  
S de Graaf ◽  
CA Fulcher
Keyword(s):  
Factor Viii ◽  
Human Factor ◽  
Factor Viii Inhibitor ◽  
Type I ◽  
Protein Fragments ◽  
Human Factor Viii ◽  
Circulating Antibodies ◽  
A1 Domain ◽  
A2 Domain

Human factor VIII(FVIII) inhibitors are pathologic, circulating antibodies that inactivate FVIII. We have examined the location of epitopes on the FVIII protein for inhibitors from hemophilia A and nonhemophilic individuals. The inhibitors were of type I or type II in the kinetics of their inactivation of FVIII. A cDNA clone of human FVIII was used to express defined FVIII protein fragments in Escherichia coli for immunoblotting with inhibitor plasma. An epitope for 18 heavy-chain inhibitors was localized to the aminoterminal 18.3 Kd of the A2 domain. Two of these inhibitors also recognized an epitope located between A1 and A2 domains. Similarly, an epitope for 23 light- chain inhibitors was localized to the C2 domain. Weaker epitopes for 13 of the same inhibitors within the C1 and C2 domains were also observed. Four of the 23 inhibitors in addition bound strongly to the A3 domain. Most inhibitors (22 of 23) were neutralized in vitro only by the FVIII fragments to which they bound on immunoblots; however, one inhibitor that was neutralized by a fragment containing the A1 domain did not bind to it on immunoblots. Conversely, 3 of 3 inhibitors that bound to the A3 domain and 5 of 15 that bound to the A2 domain were not neutralized by the corresponding fragments. The epitope specificity of an inhibitor did not depend on its source or type. Our results show that FVIII inhibitors bind to limited areas within the heavy and light chains of FVIII. Some inhibitor plasmas contain additional antibodies that may not be inhibitory.

Reduction of the inhibitory antibody response to human factor VIII in hemophilia A mice by mutagenesis of the A2 domain B-cell epitope

Blood ◽  
2004 ◽  
Vol 104 (3) ◽  
pp. 704-710 ◽  
Author(s):  
Ernest T. Parker ◽  
John F. Healey ◽  
Rachel T. Barrow ◽  
Heather N. Craddock ◽  
Pete Lollar
Keyword(s):  
Antibody Response ◽  
Factor Viii ◽  
B Cell ◽  
Human Factor ◽  
Hemophilia A ◽  
Cell Epitope ◽  
Inhibitory Antibody ◽  
B Cell Epitope ◽  
Human Factor Viii ◽  
Inhibitory Antibodies

AbstractApproximately 25% of patients with hemophilia A develop inhibitory antibodies after treatment with factor VIII. Most of the inhibitory activity is directed against epitopes in the A2 and C2 domains. Anti-A2 inhibitory antibodies recognize a 25-residue segment bounded by R484-I508. Several antigenic residues in this segment have been identified, including R484, R489, and P492. The immunogenicity of purified recombinant B domain–deleted (BDD) human factor VIII molecules containing mutations at R484A/R489A or R484A/R489A/P492A was studied in hemophilia A mice. Inhibitory antibody titers in mice receiving the R484A/R489A/P492A mutant, but not the R484A/R489A mutant, were significantly lower than in mice receiving control human BDD factor VIII. The specific coagulant activity and the in vivo clearance and hemostatic efficacy in hemophilia A mice of the R484A/R489A/P492A mutant were indistinguishable from human BDD factor VIII. Thus, the inhibitory antibody response to human factor VIII can be reduced by mutagenesis of a B-cell epitope without apparent loss of function, suggesting that this approach may be useful for developing a safer form of factor VIII in patients with hemophilia A.

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