Evaluation of the role of endotoxin and cortisol on modulation of CD18 adhesion receptors in cows with mastitis caused by Escherichia coli

Eddy Roets From the Department of Physiology, Biochemistry, and Biometrics, Veterinary Faculty, University of Ghent, Salisburylaan 133, Merelbeke 9820, Belgium (Roets, Burvenich, Diez-Fraile), and the Department of Herd Health and Reproduction, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 7, Utrecht 3584 CL, Netherlands (Noordhuizen-Stassen).

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Christian Burvenich From the Department of Physiology, Biochemistry, and Biometrics, Veterinary Faculty, University of Ghent, Salisburylaan 133, Merelbeke 9820, Belgium (Roets, Burvenich, Diez-Fraile), and the Department of Herd Health and Reproduction, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 7, Utrecht 3584 CL, Netherlands (Noordhuizen-Stassen).

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Araceli Diez-Fraile From the Department of Physiology, Biochemistry, and Biometrics, Veterinary Faculty, University of Ghent, Salisburylaan 133, Merelbeke 9820, Belgium (Roets, Burvenich, Diez-Fraile), and the Department of Herd Health and Reproduction, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 7, Utrecht 3584 CL, Netherlands (Noordhuizen-Stassen).

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Elsbeth N. Noordhuizen-Stassen From the Department of Physiology, Biochemistry, and Biometrics, Veterinary Faculty, University of Ghent, Salisburylaan 133, Merelbeke 9820, Belgium (Roets, Burvenich, Diez-Fraile), and the Department of Herd Health and Reproduction, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 7, Utrecht 3584 CL, Netherlands (Noordhuizen-Stassen).

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Abstract

Objective

To determine the effect of mastitis caused by Escherichia coli on expression of CD18 cell surface receptors and to evaluate the involvement and regulation of receptors by lipopolysaccharide (LPS) and cortisol.

Animals

11 clinically normal lactating Holstein-Friesian cows.

Procedure

Binding of CD18 monoclonal antibodies to neutrophils was studied, using flow cytometry, before and after intramammary inoculation of E coli organisms. Effect of LPS and cortisol on expression of adhesion receptors was investigated, using a whole-blood model.

Results

Expression of CD18 adhesion receptors on bovine neutrophils increased 35% by 12 hours after intramammary inoculation of E coli. By 24 hours after inoculation, the number of receptors had returned to control values. High cortisol concentrations (100 nmol/L) were seen 12 to 18 hours after inoculation. Addition of LPS to blood induced a 30% increase in the number of CD18 receptors, and maximal number of receptors was expressed at an LPS concentration of 0.1 ng/ml. A decrease in the number of CD18 receptors was induced by incubation with cortisol or dexamethasone before challenge-exposure with LPS.

Conclusions

An increase in the number of CD18 receptors on neutrophils is mediated by local production of LPS. Subsequent endogenous release of cortisol may prevent additional increases in the number of receptors.

Clinical Relevance

During acute mastitis caused by E coli, there is an increase in the number of CD18 receptors on circulating neutrophils. Cortisol induces a decrease in the number of CD18 receptors, probably modulating the acute inflammatory response in mammary glands of lactating cows. (Am J Vet Res 1999;60:534–540)

Abstract

Objective

To determine the effect of mastitis caused by Escherichia coli on expression of CD18 cell surface receptors and to evaluate the involvement and regulation of receptors by lipopolysaccharide (LPS) and cortisol.

Animals

11 clinically normal lactating Holstein-Friesian cows.

Procedure

Binding of CD18 monoclonal antibodies to neutrophils was studied, using flow cytometry, before and after intramammary inoculation of E coli organisms. Effect of LPS and cortisol on expression of adhesion receptors was investigated, using a whole-blood model.

Results

Expression of CD18 adhesion receptors on bovine neutrophils increased 35% by 12 hours after intramammary inoculation of E coli. By 24 hours after inoculation, the number of receptors had returned to control values. High cortisol concentrations (100 nmol/L) were seen 12 to 18 hours after inoculation. Addition of LPS to blood induced a 30% increase in the number of CD18 receptors, and maximal number of receptors was expressed at an LPS concentration of 0.1 ng/ml. A decrease in the number of CD18 receptors was induced by incubation with cortisol or dexamethasone before challenge-exposure with LPS.

Conclusions

An increase in the number of CD18 receptors on neutrophils is mediated by local production of LPS. Subsequent endogenous release of cortisol may prevent additional increases in the number of receptors.

Clinical Relevance

During acute mastitis caused by E coli, there is an increase in the number of CD18 receptors on circulating neutrophils. Cortisol induces a decrease in the number of CD18 receptors, probably modulating the acute inflammatory response in mammary glands of lactating cows. (Am J Vet Res 1999;60:534–540)

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