title: Immunoglobulin isotypes and functional anti-FVIII antibodies in response to FVIII treatment in Balb/c and C57BL/6 haemophilia A mice.
abstract: Previous studies have demonstrated that genetic factors play an important role in determining the likelihood of formation of anti-factor VIII (FVIII) antibodies in haemophilia A patients. We were interested in characterizing the spectrum of FVIII antibody formation and the primary and secondary immune responses after FVIII administration in two different exon 16-disrupted haemophilia A mouse strains, Balb/c and C57BL/6. Balb/c and C57BL/6 E16 haemophilia A mice were used in all experiments. Total FVIII antibodies and FVIII inhibitors were measured using ELISA and Bethesda assays respectively. T- and B-cell cytokines were quantified using ELISA and flow cytometry. FVIII antibodies, but not functional inhibitors were detectable 1 week after the first FVIII treatment in both strains. These antibodies mainly belonged to the IgM and IgA isotypes. After the fourth FVIII treatment, neutralizing anti-FVIII antibodies were detected in both mouse strains: Balb/c (mean inhibitory titer 58 BU) and C57BL/6 (mean inhibitory titer 82 BU). IgG1 levels were similar in both strains but the IgG2A and IgG2B subclasses were higher in C57BL/6 mice. The results of intracellular cytokine staining of T cells indicated that the FVIII-treated C57BL/6 mice produced more IL10 and Th1 cytokines than the FVIII-treated Balb/c mice. These studies show that C57BL/6 mice develop a stronger immune response towards FVIII than Balb/c mice. We propose that the enhanced Th1 and IL10 cytokine micro-environment induced in C57BL/6 mice is responsible for this difference. Therefore, genetic strain-dependent differences must be considered when evaluating immunological outcomes in mouse models of haemophilia A.
authors.affiliation: Department of Pathology and Molecular Medicine, Richardson Laboratory, Queen's University, Kingston, ON, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Qadura
authors.forename: B
authors.initials: B
authors.lastname: Waters
authors.forename: E
authors.initials: E
authors.lastname: Burnett
authors.forename: R
authors.initials: R
authors.lastname: Chegeni
authors.forename: C
authors.initials: C
authors.lastname: Hough
authors.forename: M
authors.initials: M
authors.lastname: Othman
authors.forename: D
authors.initials: D
authors.lastname: Lillicrap
mesh_terms: D000818:Animals; D001323:Autoantibodies / Q000097:blood*; D019774:Blood Coagulation Factor Inhibitors / Q000276:immunology; D016207:Cytokines / Q000032:analysis; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005169:Factor VIII / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology* / Q000627:therapeutic use*; D006467:Hemophilia A / Q000188:drug therapy* / Q000235:genetics / Q000276:immunology*; D007136:Immunoglobulins / Q000097:blood*; D051379:Mice; D008807:Mice, Inbred BALB C
chemical_list: D001323:Autoantibodies; D019774:Blood Coagulation Factor Inhibitors; D016207:Cytokines; D007136:Immunoglobulins; D005169:Factor VIII