title: Isolation and phagocytic properties of neutrophils and other phagocytes from nonmastitic bovine milk.
abstract: A technique for the separation of neutrophils from macrophages-epithelial cells in samples of nonmastitic bovine milk with low cell counts has been developed. The procedure is based on centrifugation in a discontinuous metrizamide gradient and is rapid, taking less than 40 min. The recovery of the neutrophils is about 30% and their viability about 90%. The isolated neutrophils showed an appreciable unstimulated luminol- and lucigenin-dependent chemiluminescence, which was due to NADPH oxidase rather than to xanthine oxidase. The neutrophils had a higher rate of ingestion of C3-opsonized particles than macrophages-epithelial cells, whereas no significant differences in phagocytosis of IgG-opsonized yeast or unopsonized yeast were detected between the two cell populations. The macrophages-epithelial cells produced no luminol-dependent chemiluminescence and induced considerably lower activity in the lucigenin-dependent system than neutrophils, indicating that these cells contain no myeloperoxidase. Analyses of the activity of the neutrophils in response to C3-opsonized yeast particles showed that the luminol-dependent chemiluminescence of cells isolated from residual milk increased significantly over the lactation period. Moreover, a tendency to a higher phagocytosis and chemiluminescence of neutrophils isolated from residual milk than from stripping milk was indicated.
authors.affiliation: Department of Veterinary Medical Chemistry, Swedish University of Agricultural Sciences, Uppsala Biomedical Center.
authors.forename: C H
authors.initials: CH
authors.lastname: Sandgren
authors.forename: K
authors.initials: K
authors.lastname: Nordling
authors.forename: I
authors.initials: I
authors.lastname: Björk
mesh_terms: D000818:Animals; D002417:Cattle / Q000276:immunology*; D002452:Cell Count / Q000662:veterinary; D002469:Cell Separation; D005260:Female; D005434:Flow Cytometry; D008856:Microscopy, Fluorescence; D008892:Milk / Q000166:cytology / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology*; D010586:Phagocytes / Q000276:immunology*; D010587:Phagocytosis; D013194:Staining and Labeling