Leukocytes–Second Line of Defense Against Invading Mastitis Pathogens

Paape, Max; Wergin, William P.; Guidry, A.J.; Pearson, R.E.

doi:10.3168/jds.s0022-0302(79)83215-4

Cited by 170 publications

(94 citation statements)

References 20 publications

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“…Glucocorticoids (corticosteroid anti-inflammatory agents) and adrenocorticotrophic hormone (ACTH), are used in the treatment of some forms of clinical mastitis. However, ACTH at a pharmacological concentration of 200 IU and at a physiological concentration of 100 IU reduces phagocytosis of S. aureus by bovine PMN isolated from milk [129,131]. The 100 IU dose of ACTH produces a plasma glucocorticoid response similar to that observed during acute coliform mastitis [129].…”

Section: Phagocytosismentioning

confidence: 99%

“…The fine structure of circulating and mammary bovine PMN has been carefully defined [125,131]. The most prominent characteristic is the multilobulated nucleus ( Fig.…”

Section: Transmission Electron Microscopymentioning

confidence: 99%

“…However, when one considers the size and blood volume (8% body weight) of mature lactating Holstein cows, a potential pool of over 100 billion circulating mature PMN are present [131]. In addition to circulating PMN is a marginal pool of mature PMN adhering to walls of blood vessels [83].…”

Section: Granulopoiesis and Granulokineticsmentioning

confidence: 99%

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The bovine neutrophil: Structure and function in blood and milk

Paape¹,

Bannerman²,

et al. 2003

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-Migration of polymorphonuclear neutrophil leukocytes (PMN) into the mammary gland provide the first line of defense against invading mastitis pathogens. Bacteria release potent toxins that activate white blood cells and epithelial cells in the mammary gland to secrete cytokines that recruit PMN that function as phagocytes at the site of infection. While freshly migrated PMN are active phagocytes, continued exposure of PMN to inhibitory factors in milk such as fat globules and casein, leads to altered PMN morphology and reduced phagocytosis. In the course of phagocytosing and destroying invading pathogens, PMN release chemicals that not only kill the pathogens but that also cause injury to the delicate lining of the mammary gland. This will result in permanent scarring and reduced numbers of milk secretory cells. The life span of PMN is limited by the onset of apoptosis. To minimize damage to mammary tissue, PMN undergo a specialized process of programmed cell death known as apoptosis. Macrophages quickly engulf and phagocytose apoptotic PMN, thereby minimizing the release of PMN granular contents that are damaging to tissue. The PMN possess an array of cell surface receptors that allow them to adhere and migrate through endothelium and to recognize and phagocytose bacteria. One receptor found on phagocytes that is receiving considerable attention in the control of infections by Gram-negative bacteria is CD14. Binding of lipopolysaccharide (LPS) to membrane bound CD14 causes release of tumor necrosis factor-a and sepsis. Binding of LPS to soluble CD14 shed from CD14-bearing cells results in neutralization of LPS and rapid recruitment of PMN to the site of infection. Recent advances in the fields of genomics and proteomics should greatly enhance our understanding of the PMN role in controlling intramammary infections in ruminants. Further, manipulation of PMN, through either recombinant proteins such as soluble CD14 that enhance PMN response or agents that mediate PMN apoptosis, may serve as novel therapeutics for the treatment of mastitis.

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Section: Phagocytosismentioning

confidence: 99%

“…The fine structure of circulating and mammary bovine PMN has been carefully defined [125,131]. The most prominent characteristic is the multilobulated nucleus ( Fig.…”

Section: Transmission Electron Microscopymentioning

confidence: 99%

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The bovine neutrophil: Structure and function in blood and milk

Paape¹,

Bannerman²,

et al. 2003

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“…The incidence of udder infection and clinical mastitis is usually highest at calving and during early lac- (37)(38)(39)43). Because of the presence of epithelial cells in milk, Paape (41) coined the phrase 'milk somatic cells', which is now used internationally as the accepted terminology.…”

Section: Introductionmentioning

confidence: 99%

“…Okano A, and Tomizuka T. Ultrasonic observation of postpartum uterine involution in the cow. 43. Wiel DFM van de, Koops W, Vos E, Nasir Hussain Shah S, Verdura Barrios T, Vendrig AAA, and Adrichem Boogaert DH van.…”

mentioning

confidence: 99%

Role of the neutrophil leucocyte in the local and systemic reactions during experimentally induced e.coli mastitis in cows immediately after calving

Burvenich

Paape

Hill

et al. 1994

Veterinary Quarterly

Self Cite

117

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Immune Surveillance of Mammary Tissue by Phagocytic Cells

Paape¹,

Shafer‐Weaver²,

Capuco

et al. 2002

Advances in Experimental Medicine and Biology

112

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The leukocytes in milk consist of lymphocytes, neutrophil polymorphonuclear leukocytes (PMN) and macrophages. Lymphocytes together with antigen-presenting cells function in the generation of an effective immune response. Lymphocytes can be divided into two distinct subsets, T- and B-lymphocytes, that differ in function and protein products. The professional phagocytic cells of the bovine mammary gland are PMN and macrophages. In the normal mammary gland macrophages are the predominate cells which act as sentinels to invading mastitis causing pathogens. Once the invaders are detected, macrophages release chemical messengers called chemoattractants that cause the directed migration of PMN into the infection. Migration of neutrophils into mammary tissue provides the first immunological line of defense against bacteria that penetrate the physical barrier of the teat canal. However, their presence is like a double-edged sword. While the PMN are phagocytosing and destroying the invading pathogens, they inadvertently release chemicals which induces swelling of secretory epithelium cytoplasm, sloughing of secretory cells, and decreased secretory activity. Permanent scarring will result in a loss of milk production. Resident and newly migrated macrophages help reduce the damage to the epithelium by phagocytosing PMN that undergo programmed cell death through a process called apoptosis. Specific ligands on the neutrophil surface are required for directed migration and phagocytosis. In response to infection, freshly migrated leukocytes express greater numbers of cell surface receptors for immunoglobulins and complement and are more phagocytic than their counterparts in blood. However, phagocytic activity rapidly decreases with continued exposure to inhibitory factors such as milk fat globules and casein in mammary secretions. Compensatory hypertrophy in non-mastitic quarters partially compensates for lost milk production in diseased quarters. Advances in molecular biology are making available the tools, techniques, and products to study and modulate host-parasite interactions. For example the cloning and expression of proteins that bind endotoxin may provide ways of reducing damaging effects of endotoxin during acute coliform mastitis. The successful formation of bifunctional monoclonal antibodies for the targeted lysis of mastitis causing bacteria represents a new line of therapeutics for the control of mastitis in dairy cows.

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Leukocytes–Second Line of Defense Against Invading Mastitis Pathogens

Cited by 170 publications

References 20 publications

The bovine neutrophil: Structure and function in blood and milk

The bovine neutrophil: Structure and function in blood and milk

Role of the neutrophil leucocyte in the local and systemic reactions during experimentally induced e.coli mastitis in cows immediately after calving

Immune Surveillance of Mammary Tissue by Phagocytic Cells

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