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  • Author or Editor: Montserrat Serra x
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Abstract

Objective—To identify extracellular proteoglycans produced by canine melanoma cell lines and analyze the effect of transforming growth factor-β1 (TGF-β1), insulin-like growth factor-I (IGF-I), and hepatocyte growth factor (HGF) on these proteoglycans.

Sample Population—3 canine melanoma cell lines (ie, CML-1, CML-6M, and CML-10c2).

Procedure—Extracellular proteoglycans were analyzed by use of metabolic labeling and western immunoblot analysis. The effect of TGF-β1 on cell proliferation was determined by incorporation of 5- bromo-2'-deoxyuridine.

Results—The CML-1 and CML-6M melanoma cell lines produced 2 main extracellular proteoglycans. One of them was identified as versican, a proteoglycan found in undifferentiated human melanoma cell lines. The CML-10c2 cells produced a small amount of extracellular proteoglycans. Addition of TGF-β1 (1.25 to 6.25 ng/ml) increased the release of sulfated proteoglycans into the medium. The TGF-β1 had mainly a posttranslational effect, because it increased the molecular mass of the sulfated bands. Addition of IGF-I (50 ng/ml) slightly increased production of proteoglycans in the CML-6M cell line, whereas HGF (50 ng/ml) did not have any effect on proteoglycan production.

Conclusions and Clinical Relevance—The proteoglycan content and response to TGF-β1 treatment for CML-1 and CML-6M canine melanoma cell lines are similar to that for undifferentiated human melanoma cell lines. In contrast, CML-10c2 cells produced a low amount of proteoglycans with high molecular weight. Because these extracellular proteoglycans are involved in the control of cell adhesion, proliferation, and migration, they may play an important role in the progression of melanomas in dogs. (Am J Vet Res 2002;63:1151–1158)

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 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