Nearly all tissues, organs, and serosal cavities harbor a population of resident phagocytes. Most contain only a diffuse scattering of individual phagocytic cells that remain inconspicuous under normal conditions and are very similar to one another in appearance and function. In some tissues, however, phagocytes are especially abundant or have distinctive morphologic features and are known by specific names. Examples include the Kupffer cells that line sinusoids of the liver (and account for nearly 10% of total liver mass), osteoclasts in bone, or microglial cells of the brain (Table bellow). (more…)
Once it is tethered onto the venule wall, the neutrophil or other leukocyte comes into contact with a wide variety of inflammatory ...
Neutrophils make up an army of more-or-less identical circulating phagocytes that are poised to respond quickly and in vast numbers ...
Our understanding of hematopoiesis has advanced greatly in recent years with the isolation and characterization of hematopoietic st ...
The process by which blood cells grow, divide, and differentiate in the bone marrow is called hematopoiesis. Three general cl ...
Toll-like receptors (TLRs) act as receptors for numerous stimuli of immune cells, including bacterial cell wall constituents (l ...
With the exception of complement protein C3, most soluble mediators of innate immunity are found in relatively small amounts in the serum under normal conditions. The concentrations of several of these proteins, however, can increase as much as 1000-fold during serious infections or other crises, as part of a coordinated protective reaction called the acute-phase response. In this response, the liver temporarily increases its synthesis of more than 30 different serum proteins, often called acute-phase proteins (Table bellow). Many of these, such as complement factors C3 and B, MBL, LBP, C-reactive protein, and serum amyloid protein P, participate in antimicrobial defense. (more…)
Acute phase proteins are plasma proteins, the synthesis and the circulating concentrations of which are adaptively regulated in res ...
Most acute phase proteins are synthesized in the liver, although the genes for some are also expressed in cells and tissues els ...
There is considerable diversity among acute phase proteins with respect to the concentrations attained, their structures, and their ...
Acute phase proteins and the acute phase response in general arc stably conserved in evolution and are universal within each specie ...
An especially elaborate and important type of innate antimicrobial enzymes defense is provided by a group of serum proteins tha ...
Perhaps the most exciting recent advance in the cytokine signaling field has been the elucidation of the Jak/Stat pathway. The Janus kinase (Jak) family consists of four known enzymes (Jak1, Jak2, Jak3, and Tyk2), each of which associates specifically with the cytoplasmic tails of one or more cytokine receptor subunits. For example, IL-2R associates with both Jak1 and Jak3, which bind its α and γ subunits, respectively. Cytokine binding brings the receptor subunits together and allows the associated Jak proteins to phosphorylate and activate one another. The primary substrates of the activated Jaks are a family of transcription factors called the Stat (for signal transducers and activators of transcription) proteins. The Stat proteins contain SH2 domains and so are recruited to the vicinity of an activated receptor when its kinases become active. (more…)
The overlapping functions of cytokines largely reflect the properties of the cell surface receptors to which they bind. All cyt ...
The Ras-dependent pathway can be triggered by a variety of cytokine receptors, as well as by certain adhesion molecules and by ...
Hematopoietic progenitors depend on a variety of cytokines to control their growth and differentiation. These include several d ...
Although it is commonly imagined that hematopoiesis takes place in a liquid environment resembling the blood, with progenitors resp ...
Our understanding of hematopoiesis has advanced greatly in recent years with the isolation and characterization of hematopoietic st ...
AP-1 is an inducible transcription factor that binds to promoter or enhancer regions of many cytokine genes, often in close association with the nuclear factor of activated T cells (NF-AT). AP-1 is composed of c-fos and c-jun or c-jun/c-jun homodimers. AP-1 binding has been demonstrated as obligatory for NF-AT-mediated cytokine gene acti- vation in many cases. The signal transduction pathway responsible for AP-1 activation involves jun and p38 kinase-activated protein kinase). (more…)
The overlapping functions of cytokines largely reflect the properties of the cell surface receptors to which they bind. All cyt ...
Perhaps the most exciting recent advance in the cytokine signaling field has been the elucidation of the Jak/Stat pathway. The ...
The Ras-dependent pathway can be triggered by a variety of cytokine receptors, as well as by certain adhesion molecules and by ...
The T-bet (T-box 21) gene (TBX21) encodes a transcription factor, T-box expressed in T cells, which has been implicated in asthma t ...
A previous genome-wide screen for mite-sensitive atopic dermatitis asthma in Japanese families indicated linkage to chromosome 5q33 ...
Sulfur Dioxide
The effects of SO2 have been extensively reviewed. Total emergency room visits for respiratory problems and increased hospital admission rates have been linked with increased ambient exposure to SO2. In children, decreased lung function has been linked to increases in ambient sulfur dioxide levels and the likelihood (more…)
Recent data show that monitoring of exposure to acid aerosols is widespread in North America, the associations in a joint statement ...
The geographical variation in the prevalence of asthma in children does not coincide with variations in air pollution levels. The i ...
Environmental pollution not only makes asthma worse we are, but could make asthma inhalers were less effective. It is the conclu ...
The Misery Of Allergies As a young boy I was one of the kids who had to stay indoors to avoid the misery that came with snee ...
The two strongest risk factors for asthma in childhood are a family history and immediate hypersensitivity to common allergens. ...
Bacteria cause allergic disease because of toxicity, invasiveness, immunopathology, or lends of these three mechanisms. Thus much of the interaction between a given bacterial species and the cellular immune response can be predicted by considering the immunological mechanisms available in relation to the mechanism of pathogenicity, and the structure of the bacterium. For a toxigenic bacterium, neutralizing antigen & antibody may be all that is needed. Otherwise destruction of the organism itself may be required. (more…)
One especially favored target for immune recognition is bacterial lipopolysaccharide (LPS). This macromolecule is found only in ...
Exotoxins are noxious proteins secreted by many bacteria. These toxins are often heat-labile and thus can be heat-inactivated f ...
Innate immune responses are seen in a very broad range of tissues. Indeed, the Toll-like receptors (TLRs, one of the most important ...
An especially elaborate and important type of innate antimicrobial enzymes defense is provided by a group of serum proteins tha ...
Once it is tethered onto the venule wall, the neutrophil or other leukocyte comes into contact with a wide variety of inflammatory ...