title: Recombinant canine IgE Fc and an IgE Fc-TRAIL fusion protein bind to neoplastic canine mast cells.
abstract: Screening for expression of the high affinity receptor for IgE by reverse transcriptase PCR, revealed that almost all canine mast cell tumors expressed FcɛRIα mRNA, supporting the rationale for developing anti-neoplastic treatments based on molecules that could target this receptor. Use of cytotoxic cytokines to trigger an apoptotic signal is one strategy for inducing cell death in malignant mast cells. The coding sequences for canine IgE and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) were identified through genome analyses. Selected regions of the coding sequences for these genes were cloned and compared to the predicted genome sequences. The Fc region of canine IgE, death domain of canine TRAIL and an IgE Fc: TRAIL fusion construct were generated and epitope-tagged proteins expressed, using a eukaryotic expression system. Specific binding of recombinant canine IgE Fc-containing proteins to recombinant human FcɛRIα and to a canine mast cell tumor line expressing FcɛRIα (C2), but not one failing to express FcɛRIα (MCLA), was demonstrated. Specific binding of the IgE: TRAIL fusion protein was not abrogated by the TRAIL moiety. These results are proof of principle that canine IgE targeting to FcɛRIα can be used as a platform for selective delivery of therapies to FcɛRIα-expressing cells, potentially enhancing their therapeutic index and efficacy.
authors.affiliation: Hospital for Small Animals, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK. Electronic address: richard.elders@ed.ac.uk.
authors.forename: R C
authors.initials: RC
authors.lastname: Elders
authors.affiliation: Department of Pathology and Infectious Diseases, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, Hertfordshire, UK.
authors.forename: A
authors.initials: A
authors.lastname: Holder
authors.affiliation: Department of Pathology and Infectious Diseases, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, Hertfordshire, UK.
authors.forename: K C
authors.initials: KC
authors.lastname: Smith
authors.affiliation: Willows Veterinary Centre and Referral Service, Highlands Road, Solihull B90 4NH, West Midlands, UK.
authors.forename: S J
authors.initials: SJ
authors.lastname: Baines
authors.affiliation: Department of Pathology and Infectious Diseases, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, Hertfordshire, UK.
authors.forename: B
authors.initials: B
authors.lastname: Catchpole
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D001706:Biopsy / Q000662:veterinary; D015153:Blotting, Western / Q000662:veterinary; D045744:Cell Line, Tumor; D003001:Cloning, Molecular; D004283:Dog Diseases / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D004285:Dogs; D005260:Female; D005434:Flow Cytometry; D008297:Male; D008407:Mast Cells / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D012313:RNA / Q000737:chemistry / Q000235:genetics; D017455:Receptors, IgE / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000276:immunology / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D012878:Skin Neoplasms / Q000276:immunology / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
chemical_list: D017455:Receptors, IgE; D011993:Recombinant Fusion Proteins; D053221:TNF-Related Apoptosis-Inducing Ligand; D012313:RNA
keywords: IgE; Immunoconjugate; Immunotherapy; Mast cell tumor; TRAIL