Ovalbumin fused with diphtheria toxin protects mice from ovalbumin induced anaphylactic shock

Abstract

For those with allergy, vaccination with a specific allergen has often been used as a major therapeutic measure. However, the universal application of this technique in clinics have been restricted due to its low success rates and the risk of active systemic anaphylactic shock (ASAS). In this regard, we constructed a fusion protein (OVA-DT), ovalbumin (OVA) fused with diphtheria toxin protein (DT), which may exert a specific cytotoxicity to cells bearing OVA-specific IgE. Its therapeutic effect was evaluated in mice (BALB/c) sensitized with OVA (Os-mice). OVA challenges to the OVA-sensitized mice (Os-mice) caused ASAS to death within 30 min, but OVA-DT treatment afforded mice complete protection. When OVA-DT was treated to the Os-mice, none showed the signs of ASAS when re-challenged 48 h after the treatment. OVA-DT itself was not found to be toxic or allergenic in normal mice. The effect of OVA-DT on the biological functions of mast cells was also studied. Binding of OVA-DT to OVA-specific IgE bearing mast cells and the inhibition of histamine release from these cells were observed. In addition, OVA-DT treatment inhibited the proliferation of OVA-specific B cells in mice. In Os-mice treated with OVA-DT, levels of anti-OVA IgG2a in serum and the production of IFN-gamma by splenic lymphocytes were found to increase, but the production of IL-4 by these cells decreased. Re-direction of cytokine profiles from OVA-specific Th2 to OVA-specific Thl is suggested. These results indicate that OVA-DT can protect Os-mice from ASAS due to OVA challenge, because it inactivates OVA-specific IgE-expressing cells, including mast cells and B cells.

Establishment of high reciprocal connectivity between clonal cortical neurons is regulated by the Dnmt3b DNA methyltransferase and clustered protocadherins

“…The modification of the BACs was verified by PCR. Finally, using homologous recombination, the BAC DNA fragment containing the Myc-tagged venus and neo r gene was inserted into pBRSDT, which contains the gene for diphtheria toxin A in the Sal I site of pBR322 [58, 59]. The homology fragments for this recombination were amplified by the a1MVE-F and a1MVE-R primers and the a1MVF-F and a1MVF-R primers, and were subcloned into pBRSDT at the Hin dIII and Nhe I restriction sites.…”

Allergen‐specific immunosuppression by ovalbumin fused with diphtheria toxin in mice sensitized with albumins of different origin

“…It was demonstrated that OVA–DT protects OVA‐sensitized mice from fatal anaphylactic shock caused by OVA challenge. And also, it was found that OVA–DT in the presence of mouse anti‐OVA serum binds to mast cells, and thereby kills them [16].…”

Cutaneous Antigen Priming via Gene Gun Leads to Skin-Selective Th2 Immune-Inflammatory Responses

“…In another series of experiments, we injected OVA protein i.v. into naive or pOVA ϫ3 -skin-sensitized mice and carefully monitored mice for signs of SAS, as previously described (35). Systemic OVA injection into skin-sensitized, but not naive controls, resulted in abrupt decreased bouts of spontaneous activity and intermittent shivering that gradually worsened to no response to whisker stimuli and only slight reaction to prodding (Table I).…”

“…Core body temperature readings were performed every 10 min with a rectal probe digital thermometer (VWR). The anaphylactic reaction was evaluated and rated according to a modified SAS scoring system (35). SAS legend: 0, no sign; 1, decreased activity and piloerection; 2, loss of coordination and dyspnea; 3, no response to whisker stimuli and only slight response to prodding; 4, no response to tail pinch and progressive paresis; 5, convulsion, prostration, or coma.…”