Targeted Fc2′-3-PE40 chimeric protein abolishes passive cutaneous anaphylaxis in mice

Abstract

SUMMARYThe alarming increase in the incidence of allergic diseases in the past decade has led to a clear call for more effective treatment. Recently, we reported on the construction of a chimeric protein for targeted elimination of cells expressing Fc1 RI receptors. This chimeric protein, designated Fc 2 H -3 -PE 40 , is composed of a Fc fragment of mouse IgE attached to a truncated form of Pseudomonas exotoxin. The Fc 2 H -3 -PE 40 chimeric protein was found to be highly cytotoxic to mouse mast cell lines and primary mouse mast cells. We now demonstrate that Fc 2 H -3 -PE 40 successfully prevents the development of passive cutaneous anaphylaxis reaction (PCA) in mice. Treatment with Fc 2 H -3 -PE 40 for 7 days prevented the PCA reaction in mice by 80% compared with that in control mice given only PBS. Fc 2 H -3 -PE 40M , the mutated, enzymatically inactive analogue of Fc 2 H -3 -PE 40 , did not display this activity . Fc 2 H -3 -PE 40 was also effective when given as a single dose 16 h before antigen exposure, resulting in complete inhibition of the PCA reaction. Moreover, treatment with Fc 2 H -3 -PE 40 did not cause mast cell degranulation, as the serum histamine values of mice treated with Fc 2 H -3 -PE 40 were within the range obtained for control, untreated mice. Thus, the Fc 2 H -3 -PE 40 chimeric protein offers a novel approach to the treatment of allergic disorders.

Apoptosis-Inducing Human-Origin Fcε-Bak Chimeric Proteins for Targeted Elimination of Mast Cells and Basophils: A New Approach for Allergy Treatment

“…It has been shown that treatment with Fc⑀-PEA leads to mast cells elimination in vitro (2) and prevents passive coetaneous anaphylaxis in vivo (3). Moreover, Fc⑀-PEA does not cause degranulation in vitro or in vivo (2,3). These findings indicated that the targeting of mast cells and basophils by such chimeric proteins is a promising treatment for allergic diseases.…”

“…We recently described the in vitro and in vivo activity of the chimeric protein Fc⑀-PEA, which contains the bacterial Pseudomonas exotoxin A (PEA) 3 as a killing moiety (2,3). The chimera was designed to target mast cells and basophils, the main inducers of allergic responses.…”

“…Use of the Fc portion of the mouse IgE in the Fc⑀-PEA protein allowed specific targeting of the chimera to mast cells and basophils, because only these two types of cells exhibit relatively high levels of the Fc⑀RI. It has been shown that treatment with Fc⑀-PEA leads to mast cells elimination in vitro (2) and prevents passive coetaneous anaphylaxis in vivo (3). Moreover, Fc⑀-PEA does not cause degranulation in vitro or in vivo (2,3).…”

Pseudomonas aeruginosa Exotoxin A Induces Human Mast Cell Apoptosis by a Caspase-8 and -3-dependent Mechanism

“…Because of its potent cytotoxicity, ETA has been widely used to generate fusion proteins to kill target cells. For example, chimeric cytotoxins have been constructed by the fusion of growth factors or antibodies with the enzymatic region of ETA to specifically target and eliminate cancer cells, virally infected cells, or mast cells (7)(8)(9)(10)(11)(12). It is generally accepted that ETA is internalized by the cell surface receptor CD91 (the ␣2-macroglobulin receptor/low density lipoprotein receptor-related protein) (13) and asserts its cellular toxicity by blocking protein synthesis through ADP ribosylation of translation elongation factor 2 (14 -16).…”

“…Because mast cells play an essential role in allergy, several approaches have been used to deplete mast cells, including ETA (9,10). A chimeric protein composed of an Fc fragment of mouse IgE and a truncated form of ETA demonstrates potent mast cell cytotoxicity in vitro and prevents mast cell-dependent passive cutaneous anaphylaxis in mice in vivo (9, 10).…”