Lipotechoic acid

Insect immune system comprises of both humoral and cellular defenses. Nodulation is one of the major, yet very poorly understood cellular responses against microbial infections in insects. Through screening for novel immune genes from an Indian saturniid silkmoth Antheraea mylitta, we identified a protein up-regulated in hemolymph within minutes upon bacterial challenge. We have shown here, for first time, the involvement of this novel protein in mediating nodulation response against bacteria and hence designated it as Noduler...

Biological response modifiers (BRMs) are substances which augment immune response. BRMs can be cytokines which are produced endogenously in our body by immune cells or derivatives of bacteria, fungi, brown algae, Aloe vera and photosynthetic plants. Such exogeneous derivatives (exogeneous BRMs) can be nucleic acid (CpG), lipid (lipotechoic acid), protein or polysaccharide in nature. The receptors for these exogeneous BRMs are pattern recognition receptors. The binding of exogeneous BRMs to pattern recognition receptors triggers immune response...

Mastitis is one of the most costly diseases of agriculturally important animals and is a common problem for lactating cows. Current methods used to detect clinical and especially subclinical mastitis are either inadequate or problematic. Pathogens such as the gram-positive bacterium Staphylococcus aureus or the gram-negative bacterium Escherichia coli typically cause mastitis. E. coli induces clinical mastitis, whereas, S. aureus causes a subclinical, chronic infection of the mammary gland. In this study we report the differential expression and secretion of mammary-derived serum amyloid A3 (SAA3) by bovine mammary epithelial cells following stimulation with the S...

OBJECTIVES: The primary aetiologic factor of periodontal disease is the bacterial biofilm. Gram-positive and gram-negative bacteria possess a plethora of structural or secreted components that may cause direct destruction to periodontal tissues or stimulate host cells to activate a wide range of inflammatory responses. These responses are intended to eliminate the microbial challenge, but may often cause further tissue damage. METHODS: This review has been divided into three parts: (a) bacterial virulence factors, which includes basic information on bacterial virulence factors, and the principle inflammatory responses that host cells elicit against these factors, (b) main receptors and signalling pathways, which includes basic information about the main receptors that interact with the bacterial virulence factors, the nature of these interactions, and the activated signalling pathways that lead to inflammatory responses, and (c) initiation of inflammation, which includes a model by which the virulence factors may interact with host cells and lead to inflammatory responses in the gingiva...

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Macrophage-derived secretory leukocyte protease inhibitor (SLPI) can be induced locally as well as systemically in response to microbial products such as LPS and lipotechoic acid. It is not known whether phagocytosis of apoptotic cells, an essential function of macrophages, can regulate expression and secretion of SLPI. In this study, we report that exposure of peritoneal macrophages of BALB/c mice or murine macrophage cell lines RAW264.7 and J774.1 to apoptotic target cells induced an elevation in SLPI secretion...

OBJECTIVE: In the pathogenesis of septic shock, caused by either bacterial toxins or trauma, increased production of multiple proinflammatory mediators, such as phospholipase A(2) (PLA(2)), cytokines, and chemokines, is known to be of major importance. The present study was undertaken to investigate the influence of a newly designed extracellular PLA(2) inhibitor (ExPLI) on synthesis of proinflammatory mediators and mortality rate in a rat sepsis model. DESIGN: Prospective, randomized animal study...

Intestinal epithelial cells (IEC) interact with a high density of Gram-positive bacteria and are active participants in mucosal immune responses. Recognition of Gram-positive organisms by Toll-like receptor (TLR)2 induces proinflammatory gene expression by diverse cells. We hypothesized that IEC are unresponsive to Gram-positive pathogen-associated molecular patterns and sought to characterize the functional responses of IEC to TLR2-specific ligands. Human colonic epithelial cells isolated by laser capture microscopy and IEC lines (Caco-2, T84, HT-29) were analyzed for expression of TLR2, TLR6, TLR1, and Toll inhibitory protein (Tollip) mRNA by RT-PCR and quantitative real-time PCR...

The urokinase-type plasminogen activator receptor (uPAR, CD87) is a highly glycosylated 55- to 60-kDa protein anchored to the cell membrane through a glycosylphosphatidylinositol moiety that promotes the acquisition of plasmin on the surface of cells and subsequent cell movement and migration by binding urokinase-type plasminogen activator. uPAR also occurs in a soluble form in body fluids and tumor extracts, and both membrane and soluble uPAR are overexpressed in patients with tumors. uPAR may be a factor in inflammatory disorders as well...

Macrophages are a cellular cornerstone of the innate immune response. The outcome of macrophage activity during development of an immune response to microbes results from macrophage activation by both organism-derived and host-derived factors. In order to more fully understand the spectrum of responses expressed by macrophages when encountering these distinct stimuli, we investigated the similarities and differences between interferon-gamma receptor (IFN-gammaR)-dependent macrophage activation and stimulation of macrophages through the Type A1 scavenger receptor (SR)...

The activation of leucocytes by bacterial cell wall lipopolysaccharide (LPS) contributes to the pathogenesis of septic shock. LPS is known to interact with several cell-surface proteins, including CD14, when presented as a complex with serum LPS-binding protein. However, the identity of the receptor responsible for LPS signalling and leucocyte activation is unknown. Interestingly, mice deficient in cell-surface L-selectin were dramatically resistant to the lethal effects of high doses of LPS in a model of septic shock...

In vitro tissue culture techniques were employed to study the effects of bacterial endotoxins on the growth of normal epithelial cells from the human ureter (NHU). Primary cultures of NHU cells were initiated from explant outgrowth cultures of human ureteral tissue and cultured on collagen gel in F-12* medium containing 1% fetal calf serum (FCS). Optimal clonal growth of secondary cultures of NHU cells seeded at relatively low seeding cell densities, directly on plastic dishes, was achieved in F-12* medium containing bovine pituitary extract (0...

Human blood monocytes in culture gradually lose their capability to produce superoxide when stimulated. Addition of 10(-8) M 1,25-dihydroxyvitamin D3 [1, 25(OH)2D3], 2.5 ng/ml LPS, or 25 ng/ml lipotechoic acid (LTA) prevented this decrease in monocyte respiratory burst when added at initiation of culture. Monocytes cultured for 4 days in the presence of 1,25 (OH)2D3, LPS, or LTA retained the ability to produce superoxide and 1,25 (OH)2D3 actually increased the oxidative capacity compared with fresh monocytes...

Human parotid saliva was investigated for the presence of IgA antibodies reacting with Streptococcus mutans, lipotechoic acid (LTA) and peptidoglycan. By using an enzyme-linked immunosorbent assay, ELISA, it was shown that the salivas of 12 subjects contained antibodies reacting with S. mutans serotype c and d and with LTA. Six salivas were tested against peptidoglycan but these tests indicated only low levels of antibodies. Absorption of saliva with whole cells of S. mutans inhibited the homologous reaction by up to 87% and the reaction with LTA by up to 52%...