Advertisement

Comparison of L-selectin and Mac-1 expression on blood and milk neutrophils during experimental Escherichia coli-induced mastitis in cows

Araceli Diez-FrailleDepartment of Physiology, Biochemistry and Biometrics, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.

Search for other papers by Araceli Diez-Fraille in
Current site
Google Scholar
PubMed
Close
 DVM, PhD
,
Jalil MehrzadDepartment of Physiology, Biochemistry and Biometrics, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
Present address is the Department of Animal Science, McGill University, 21111 Lakeshore Rd, Ste. Anne de Bellevue, QC, H9X 3V9, Canada; and the Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada, PO Box 90, 2000 Route 108 E, Lennoxville, QC, J1M 1Z3, Canada.

Search for other papers by Jalil Mehrzad in
Current site
Google Scholar
PubMed
Close
 DVM, PhD
,
Evelyne MeyerDepartment of Physiology, Biochemistry and Biometrics, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.

Search for other papers by Evelyne Meyer in
Current site
Google Scholar
PubMed
Close
 PhD
,
Luc DuchateauDepartment of Physiology, Biochemistry and Biometrics, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.

Search for other papers by Luc Duchateau in
Current site
Google Scholar
PubMed
Close
 PhD
, and
Christian BurvenichDepartment of Physiology, Biochemistry and Biometrics, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.

Search for other papers by Christian Burvenich in
Current site
Google Scholar
PubMed
Close
 DVM, PhD

Abstract

Objective—To evaluate L-selectin (CD62L) and Mac-1 (CD11b) expression at the surface of blood and milk neutrophils during the early inflammatory response to Escherichia coli-induced mastitis in cows.

Animals—6 healthy Holstein heifers in early lactation.

Procedure—Blood and milk samples were collected before and after intramammary administration of 104 CFU's of E coli in the left mammary gland quarters. Bacterial counts and electrolyte concentrations in milk, rectal temperature, differential blood leukocyte counts, milk somatic cell counts, neutrophil viability, and the expression of CD62L and CD11b on blood and milk neutrophils were determined longitudinally.

Results—Bacteria grew during the first 6 hours after inoculation with a pronounced leukocytic influx. Coincident with neutrophil influx was an increase in CD62L+ and CD11b+ milk neutrophils, as well as an improved viability of milk neutrophils. The peak of the inflammatory reaction was reached approximately 12 hours after E coli inoculation. From that time forward, changes in CD62L and CD11b expression were opposed to each other, with a decrease in CD62L expression and an increase in CD11b expression on blood and milk neutrophils; the magnitude of the differences in CD62L and CD11b expression between blood and milk neutrophils decreased. Percentages of CD62L+ and CD11b+ milk neutrophils increased to percentages that were similar to blood neutrophils (ie, approx 92%).

Conclusions and Clinical Relevance—The presence of adhesion molecules on a large percentage of milk neutrophils during the acute inflammatory response, together with the changes in receptor density, suggest a major role for CD62L and CD11b in neutrophil function during coliform mastitis. (Am J Vet Res 2004;65:1164–1171)

Abstract

Objective—To evaluate L-selectin (CD62L) and Mac-1 (CD11b) expression at the surface of blood and milk neutrophils during the early inflammatory response to Escherichia coli-induced mastitis in cows.

Animals—6 healthy Holstein heifers in early lactation.

Procedure—Blood and milk samples were collected before and after intramammary administration of 104 CFU's of E coli in the left mammary gland quarters. Bacterial counts and electrolyte concentrations in milk, rectal temperature, differential blood leukocyte counts, milk somatic cell counts, neutrophil viability, and the expression of CD62L and CD11b on blood and milk neutrophils were determined longitudinally.

Results—Bacteria grew during the first 6 hours after inoculation with a pronounced leukocytic influx. Coincident with neutrophil influx was an increase in CD62L+ and CD11b+ milk neutrophils, as well as an improved viability of milk neutrophils. The peak of the inflammatory reaction was reached approximately 12 hours after E coli inoculation. From that time forward, changes in CD62L and CD11b expression were opposed to each other, with a decrease in CD62L expression and an increase in CD11b expression on blood and milk neutrophils; the magnitude of the differences in CD62L and CD11b expression between blood and milk neutrophils decreased. Percentages of CD62L+ and CD11b+ milk neutrophils increased to percentages that were similar to blood neutrophils (ie, approx 92%).

Conclusions and Clinical Relevance—The presence of adhesion molecules on a large percentage of milk neutrophils during the acute inflammatory response, together with the changes in receptor density, suggest a major role for CD62L and CD11b in neutrophil function during coliform mastitis. (Am J Vet Res 2004;65:1164–1171)