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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bovine gamma/delta T cells and neutrophils roll on 24 h cytokine- or lipopolysaccharide-stimulated bovine fetal umbilical cord endothelial cells in assays done under physiological flow. An antibody directed against E- and L-selectin has minimal blocking effect on this rolling interaction. mAbs were raised against the stimulated bovine endothelial cells and screened for inhibition of gamma/delta T cell rolling. One mAb (GR113) was identified that recognizes an antigen (GR antigen) selectively expressed by stimulated bovine endothelial cells isolated from fetal umbilical cord, mesenteric lymph nodes, and aorta. GR113 blocked bovine gamma/delta T cell as well as neutrophil rolling on the 24 h-activated endothelial cells. The GR antigen was constitutively expressed at low levels on the cell surface of platelets and its expression was not upregulated after stimulation of these cells with thrombin or phorbol myristate acetate. However, stimulated platelets released a soluble, functionally active form of the molecule that selectively bound in solution to gamma/delta T cells in a mixed lymphocyte preparation. GR113 mAb blocked the binding of the soluble platelet molecule to the gamma/delta T cells. Soluble GR antigen also bound a subset of human lymphocytes. Cutaneous lymphocyte-associated antigen (CLA) bright human lymphocytes exhibited the greatest capacity to bind the GR antigen, though CLA was not required for binding. Subsets of both human CD4 and CD8 T cells bound the GR antigen. Immunoprecipitation experiments showed the GR antigen to be 110-120 kD Mr. The binding of soluble GR antigen was inhibited by EDTA and O-sialoglycoprotease, but not neuraminidase treatment of the target cells.
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PMID:Characterization of an adhesion molecule that mediates leukocyte rolling on 24 h cytokine- or lipopolysaccharide-stimulated bovine endothelial cells under flow conditions. 936 30

Respiratory infections which commonly occur in sheep and goats often result from adverse physical and physiological stress combined with viral and bacterial infections. Inevitably, Pasteurella haemolytica pneumonia occurs as a result of these interactions. In this review, we present recent advances in research on the complex etiology of pneumonia involving P. haemolytica. Initially stress, induced by factors such as heat, overcrowding, exposure to inclement weather, poor ventilation, handling and transport is a major predisposing factor. Respiratory viruses including parainfluenza 3 (PI-3) virus, adenovirus type 6 and respiratory syncytial virus (RSV), and to a lesser extent bovine adenovirus type 2, ovine adenovirus types 1 and 5, and reovirus type 1 cause respiratory infections and pneumonia. More importantly these viruses also dramatically increase the susceptibility of sheep and goats to secondary P. haemolytica infection. Primary infection of the lower respiratory tract, with Mycoplasma ovipneumoniae and Bordetella parapertussis can increase the susceptibility of sheep and goats to secondary P. haemolytica infection. It is possible that initial infections with viral or primary bacterial agents break down the antimicrobial barrier consisting of beta defensins and anionic peptides found in epithelial cells, resident and inflammatory cells, and serous and mucous secretions of the respiratory tract. Loss of barrier integrity may release P. haemolytica from its usual commensal status. Once in the lung, P. haemolytica becomes opportunistic. To grow and colonize, P. haemolytica uses extracellular products like O-sialoglycoprotein endopeptidase, neuraminidase and RTX leukotoxin, as well as cell-associated products such as capsular polysaccharide, lipopolysaccharide, outer membrane proteins, proteins involved in iron acquisition and a periplasmic superoxide dismutase. In lambs and kids, pneumonic pasteurellosis can be acute, characterized by fever, listlessness, poor appetite and sudden death. Sheep and goats that survive the acute stage may recover or become chronically affected showing reduced lung capacity and weight gain efficiency and sporadic deaths may occur. This infection is detrimental to sheep and goats throughout the world and flocks and herds of small ranches, dairy operations, or large feedlots are all affected.
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PMID:Pasteurella haemolytica complicated respiratory infections in sheep and goats. 968 40

Mannheimia haemolytica (previously known as Pasteurella haemolytica) is a weakly hemolytic, gram-negative coccobacillus that is an opportunistic pathogen of cattle, sheep and other ruminants. In stressed, immunocompromised animals, the organism causes a fibrinous, necrotic pneumonia, commonly called "shipping fever". In the United States, economic losses due to shipping fever pneumonia surpass the combined cost of all other diseases of cattle. M. haemolytica, which is a member of the family Pasteurelleaceae, includes twelve serotypes (A1, A2, A5-A9, A12-14, A16 and A17) based on capsular antigen typing. Worldwide, serotypes A1 and A2 predominate, though all serotypes can cause disease. Serotype A1 causes pasteurellosis in cattle and has been the subject extensive study, while serotype A2 causes disease in sheep and is less-well characterized. Potential virulence factors of M. haemolytica have been identified and characterized by gene cloning and DNA sequence analysis. These factors include a ruminant-specific leukotoxin, an anti-phagocytic capsule, lipopolysaccharide, iron-regulated outer membrane proteins, lipoproteins, a sialoglycoprotease, a neuraminidase and two potential immunoglobulin proteases. Unlike the well-characterized leukotoxin, little is known about the expression of these other virulence factors. Attempts to dissect the mechanisms of M. haemolytica pathogenesis have been hindered by the lack of a robust genetic system for mutation of the organism, though new tools for genetic manipulation of M. haemolytica have been developed. Expression plasmids and operon fusion plasmids have been created and a series of antibiotic resistance cassettes useful for site-specific recombination have been constructed. It is anticipated that use of these tools for gene expression and mutagenesis, in combination with the soon to be released genomic sequence of a serotype A1 organism, will aid in understanding the molecular mechanisms of pathogenesis of M. haemolytica and will help to drive development of new vaccines to prevent shipping fever.
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PMID:Molecular genetic analysis of virulence in Mannheimia (pasteurella) haemolytica. 1153 7

Mannheimia haemolytica is the principal bacterium isolated from respiratory disease in feedlot cattle and is a significant component of enzootic pneumonia in all neonatal calves. A commensal of the nasopharynx, M. haemolytica is an opportunist, gaining access to the lungs when host defenses are compromised by stress or infection with respiratory viruses or mycoplasma. Although several serotypes act as commensals, A1 and A6 are the most frequent isolates from pneumonic lungs. Potential virulence factors include adhesin, capsular polysaccharide, fimbriae, iron-regulated outer membrane proteins, leukotoxin (Lkt), lipopolysaccharide (LPS), lipoproteins, neuraminidase, sialoglycoprotease and transferrin-binding proteins. Of these, Lkt is pivotal in induction of pneumonia. Lkt-mediated infiltration and destruction of neutrophils and other leukocytes impairs bacterial clearance and contributes to development of fibrinous pneumonia. LPS may act synergistically with Lkt, enhancing its effects and contributing endotoxic activity. Antibiotics are employed extensively in the feedlot industry, both prophylactically and therapeutically, but their efficacy varies because of inconsistencies in diagnosis and treatment regimes and development of antibiotic resistance. Vaccines have been used for many decades, even though traditional bacterins failed to demonstrate protection and their use often enhanced disease in vaccinated animals. Modern vaccines use culture supernatants containing Lkt and other soluble antigens, or bacterial extracts, alone or combined with bacterins. These vaccines have 50-70% efficacy in prevention of M. haemolytica pneumonia. Effective control of M. haemolytica pneumonia is likely to require a combination of more definitive diagnosis, efficacious vaccines, therapeutic intervention and improved management practices.
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PMID:Mannheimia haemolytica and bovine respiratory disease. 1821 56