Long-term induction of immune tolerance after blockade of CD40-CD40L interaction in a mouse model of hemophilia A

Abstract

A factor VIII-deficient knockout mouse was used as a model for severe hemophilia A to characterize the immune response to recombinant human factor VIII (fVIII) and to study new approaches for induction of immune tolerance to fVIII. Mice initially received periodic injections of fVIII in doses similar to those used for the treatment of human hemophilia A. To induce immune tolerance, a hamster monoclonal antibody specific for murine CD40 ligand (CD40L or CD154) was injected with fVIII. Control mice received fVIII alone or fVIII and hamster immunoglobulin G. After treatment, humoral and cellular immune responses were evaluated. Ninety-five percent of anti-CD40L-treated mice had lower titers of anti-fVIII antibody (less than 1 g/mL) compared with fVIII-injected control mice (mean, 18 g/mL). To determine whether anti-CD40L treatment induces long-term immune tolerance, mice were rechallenged 3 times with fVIII alone. At 150 days after treatment, 12 of 22 anti-CD40L-treated mice remained tolerant to fVIII (anti-fVIII antibody titers less than 1 g/mL). However, tolerant mice immunized with tetanus toxoid (TT) developed high anti-TT antibody, demonstrating that tolerance is fVIII specific. T cells from tolerant mice showed impaired proliferative responses after stimulation with fVIII in vitro and lack of production of the cytokines interleukin-2 (IL-2), IL-4, interferon ␥, and IL-10. These results demonstrate that long-term immune tolerance to fVIII was effectively induced after early blockade of CD40-CD40L interaction. In addition, the lack of tolerance in this model was associated with the expression of a Th2 phenotype.

Infectious Nickel Tolerance: A Reciprocal Interplay of Tolerogenic APCs and T Suppressor Cells That Is Driven by Immunization

“…The CD40-CD40L interaction required for T cell priming has been noted, among other places, in a mouse model of contact hypersensitivity (34). In most models, when the CD40-CD40L interaction was interrupted, the administration of Ag failed to induce an immune response, but instead induced tolerance (35). The spontaneous down-regulation of CD40, which we noted on the APCs of nickel-tolerized mice, is comparable with that described for other conditions of T cell unresponsiveness in mice and men (36,37).…”

Dangerous liaisons: the role of “danger” signals in the immune response to gene therapy

“…The importance of the viral DNA and protein capsid as adjuvants is emphasized by work in which ␣-CD40L was capable of inducing long-term tolerance, even on repeat administration, when recombinant hFVIII protein alone was given to hemophilic mice, and no humoral immunity developed against the exogenous protein. 97 The most critical element of the danger theory that differs from the classic SNS model is its treatment of signal 0. Here the danger theory predicts that by removing signal 0 the initiation of an immune response can be avoided.…”

Indoleamine 2,3-dioxygenase attenuates inhibitor development in gene-therapy-treated hemophilia A mice

“…[14][15][16][17][18] The protein B7, which is expressed on the surface of antigen-presenting cells, interacts with CD28 expressed on T cells, thereby activating T-cell proliferation and promoting the humoral response to FVIII. 14,17 Cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) is a second high-affinity T-cell receptor for the B7 ligand, and is a negative regulatory of T-cell activation.…”