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  • Author or Editor: Pilar Brazís x
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Abstract

Objective—To assess binding of IgE to native, whole hydrolyzed, and separated hydrolyzed fractions of soy protein in serum obtained from dogs with experimentally induced soy protein hypersensitivity.

Animals—8 naïve Beagles (6 experimentally sensitized to native soy protein and 2 control dogs).

Procedures—6 dogs were sensitized against soy protein by administration of allergens during a 90-day period. After the sensitization protocol was completed, serum concentrations of soy-specific IgE were measured and intradermal skin tests were performed in all 6 dogs to confirm that the dogs were sensitized against soy protein. Serum samples from each sensitized and control dog underwent western blot analysis to assess the molecular mass band pattern of the different allergenic soy fractions and evaluate reactivities to native and hydrolyzed soy protein.

Results—In sera from sensitized dogs, a characteristic band pattern with 2 major bands (approx 75 and 50 kd) and 2 minor bands (approx 31 and 20 kd) was detected, whereas only a diffuse band pattern associated with whole hydrolyzed soy protein was detected in the most reactive dog. Reactivity was evident only for the higher molecular mass peptide fraction. In control dogs, no IgE reaction to native or hydrolyzed soy protein was detected.

Conclusions and Clinical Relevance—Data suggest that the binding of soy-specific IgE to the hydrolyzed soy protein used in the study was significantly reduced, compared with binding of soy-specific IgE to the native soy protein, in dogs with experimentally induced soy hypersensitivity.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To assess whether dogs with experimentally induced type I hypersensitivity against soy protein would respond to soy hydrolysate and develop cutaneous or gastrointestinal tract reactions after intradermal and oral challenge exposure.

Animals—12 naïve Beagle pups (9 sensitized and 3 control dogs).

Procedure—9 dogs were sensitized against soy protein by administration of allergens during a 90-day period. After the sensitization period, serum concentrations of soy-specific IgE were determined and an intradermal test was performed to confirm the dogs were sensitized against soy protein. An intradermal challenge test and an oral challenge test with native and hydrolyzed soy protein were conducted on 6 sensitized and 2 control dogs.

Results—High serum concentrations of soy-specific IgE and positive results for the intradermal test were observed for the 9 sensitized dogs after completion of the sesitization process. Sensitized dogs challenge exposed with hydrolyzed soy protein had a reduced inflammatory response after intradermal injection and no clinical response after an oral challenge exposure, compared with responses after intradermal and oral challenge exposure with native soy protein.

Conclusions and Clinical Relevance—Soy-sensitized dogs did not respond to oral administration of hydrolyzed soy protein. Thus, hydrolyzed soy protein may be useful in diets formulated for the management of dogs with adverse reactions to food.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To assess expression and function of cellsurface IgE receptors on the canine mastocytoma cell line C2 maintained in continuous culture.

Sample Population—C2 cells maintained in medium lacking IgE for up to 10 passages before being stored at –80 C.

Procedure—Cells were thawed, cultured in medium without IgE for 1 to 3 passages, sensitized for 7 days with IgE-rich serum from dogs naturally sensitized to Ascaris suum, and stimulated with antigen Asc S1 from A suum, goat polyclonal anti-canine IgE, or calcium ionophore and phorbol myristate acetate (PMA). Percentage of intracellular β-hexosaminidase released and concentration of tumor necrosis factor-α (TNF-α) synthesized after stimulation were determined. Expression of cell-surface IgE receptors was assessed by use of a flow cytometry.

Results—Immunologic stimulation (antigen or anti-IgE) failed to induce release or synthesis of detectable amounts of β-hexosaminidase or TNF-α. In contrast, nonimmunologic stimulation (calcium ionophore and PMA) led to release of β-hexosaminidase (mean ± SEM maximum release, 23.95 ± 1.96%) and synthesis of TNF-α (maximum concentration, 34.34 ± 2.34 pg/106 cells). As revealed by use of flow cytometry, C2 cells expressed surface IgE receptors that bound canine IgE in vitro.

Conclusions and Clinical Relevance—Continuous culture of the canine mastocytoma cell line C2 in medium without exogenous IgE or cytokines and other growth factors resulted in cell-surface expression of nonfunctional IgE receptors. However, C2 cells maintained in continuous culture may still be a useful tool for the evaluation of mast cell responses to nonimmunologic stimulation and IgE receptor differentiation and maturity. (Am J Vet Res 2002;63:763–766)

Full access
in American Journal of Veterinary Research