title: Anti-CD3 antibodies modulate anti-factor VIII immune responses in hemophilia A mice after factor VIII plasmid-mediated gene therapy.
abstract: One major obstacle in gene therapy is the generation of immune responses directed against transgene product. Five consecutive anti-CD3 treatments concomitant with factor VIII (FVIII) plasmid injection prevented the formation of inhibitory antibodies against FVIII and achieved persistent, therapeutic levels of FVIII gene expression in treated hemophilia A mice. Repeated plasmid gene transfer is applicable in tolerized mice without eliciting immune responses. Anti-CD3 treatment significantly depleted both CD4+ and CD8+ T cells, whereas increased transforming growth factor-beta levels in plasma and the frequency of both CD4+CD25+FoxP3+ and CD4+CD25-Foxp3+ regulatory T cells in the initial few weeks after treatment. Although prior depletion of CD4+CD25+ cells did not abrogate tolerance induction, adoptive transfer of CD4+ cells from tolerized mice at 6 weeks after treatment protected recipient mice from anti-FVIII immune responses. Anti-CD3-treated mice mounted immune responses against both T-dependent and T-independent neo-antigens, indicating that anti-CD3 did not hamper the immune systems in the long term. Concomitant FVIII plasmid + anti-CD3 treatment induced long-term tolerance specific to FVIII via a mechanism involving the increase in transforming growth factor-beta levels and the generation of adaptive FVIII-specific CD4+Foxp3+ regulatory T cells at the periphery. Furthermore, anti-CD3 can reduce the titers of preexisting anti-FVIII inhibitory antibodies in hemophilia A mice.
authors.affiliation: Department of Pediatrics, Seattle Children's Research Institute and University of Washington, Seattle, WA 98101, USA.
authors.forename: Baowei
authors.initials: B
authors.lastname: Peng
authors.forename: Peiqing
authors.initials: P
authors.lastname: Ye
authors.forename: David J
authors.initials: DJ
authors.lastname: Rawlings
authors.forename: Hans D
authors.initials: HD
authors.lastname: Ochs
authors.forename: Carol H
authors.initials: CH
authors.lastname: Miao
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001323:Autoantibodies / Q000276:immunology; D001324:Autoantigens / Q000276:immunology; D017252:CD3 Complex / Q000276:immunology*; D005169:Factor VIII / Q000235:genetics* / Q000276:immunology; D005434:Flow Cytometry; D015316:Genetic Therapy / Q000379:methods*; D006467:Hemophilia A / Q000276:immunology / Q000628:therapy*; D007108:Immune Tolerance / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010957:Plasmids; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D001324:Autoantigens; D017252:CD3 Complex; D005169:Factor VIII