Requirement for Leukotriene B4 Receptor 1 in Allergen-Induced Airway Hyper-Responsiveness

Airway Hyper-Responsiveness
A role for Leukotriene B4 in the induction of airway hyper-responsiveness was explored through the use of transgenic mice deficient in the BLT1 receptor for LTB4 . Ovalbumin challenge of sensitized wild-type mice resulted in the usual features of experimental asthma, including goblet cell hyperplasia, hyper-responsiveness to inhaled methacholine and elevated BAL fluid concentrations of the Th2 cytokine IL-13. In contrast, BLT1 –/– mice (i.e. genetically modified mice lacking the gene coding for the BLT1 receptor) exhibited significantly lower responses. BLT1 –/– mice also exhibited lower numbers of IL-13-positive T lymphocytes of both the helper (CD4 T Cells) and cytotoxic/suppressor (CD8 + ) types. (more…)

Sublingual Immunotherapy Mechanisms

sublingual immunotherapy
The immunologic mechanisms of sublingual immunotherapy are less established. In Cochrane analysis, the authors concluded that there was an increase in IgG4 but no stable effect on IgE levels in adults. In addition, the induction of allergen-specific IgA has been reported. There are conflicting data concerning lympho-proliferative responses. So far the evidence on changes in Th1/Th2/Treg activity induced by sublingual immunotherapy need to be confirmed. The effects on T-cell reactivity and cytokine secretion show strong variation in a number of studies. (more…)

Treg Cells In Allergen-Specific Immunotherapy

treg cells
Treg cells or regulatory T cells constitute a large population of cellular infiltrate in atopic/allergic inflammation and a dysregulated immune response appears to be an important pathogenetic factor. Cardinal events during allergic inflammation can be classified as activation, organ-selective homing, survival and reactivation, and effector functions of immune system cells. T cells are activated by aeroallergens, food antigens, autoantigens, and bacterial exotoxins superantigens in allergic inflammation. They are under the influence of the skin, lung, or nose-related chemokine network and show organ-selective homing. (more…)

Allergen-Specific Immunotherapy Mechanisms & The Involvement Of Treg Cells

allergen specific immunotherapy
Allergen-specific immunotherapy is highly effective in the treatment of IgE-mediated allergy diseases such as rhinitis, conjunctivitis, asthma, and venom allergy hypersensitivity. It is the only treatment that leads to lifelong tolerance against previously disease-causing allergens due to restoration of the normal immunity. (more…)

Foxp3 Forkhead Winged Transcription Factor & Mechanisms Of Suppression

foxp3
The intracellular forkhead winged transcription factor Foxp3 (forkhead box P3) appears to be specifically expressed by naturally occurring Treg cells, particularly in mice, although in humans there is evidence of upregulation of Foxp3 in all T cells on activation. Foxp3 is required for the development and function of naturally occurring regulatory t cells (treg) and expression is sufficient to convert non-regulatory CD4+CD25T cells into cells with regulatory activity. Conversion of peripheral CD4+CD25 naive T cells to Foxp3+CD4+CD25 foxp3+ Treg cells can be induced by TGF-ß. In a murine asthma model, these TGF-ß-induced Treg prevented house-dust mite-induced allergic pathogenesis or infection pathogenesis in lungs. A single independent report has suggested that IL-4 and IL-13 also induce Foxp3+CD25+ Treg from CD4+CD25precursors. (more…)

CD4 CD25 Foxp3 Regulatory T Cells (Treg) Markers Occurring

regulatory t cells
Regulatory T cells Treg (picture above) is the existence of suppressor cells, which limit ongoing immune responses and prevent autoimmune disease, was postulated over 30 years ago. The recent phenotypic and functional characterization of these cells has led to a resurgence of interest in their therapeutic application in a number of immune-mediated diseases. Two broad subsets of CD3+CD4+ suppressive or Treg cells have been described: constitutive or naturally occurring versus adaptive or inducible Treg. (more…)

Allergic Responses Prevention: Regulatory T Cells (Treg)

Regulatory T Cells
The induction of immune tolerance and specific immune suppression are essential processes in the control of immune responses. Regulatory T cells (Treg) play a central role in immune control in the periphery. Two broad categories of Treg have been described: naturally occurring Treg that are present in all individuals and antigen-induced Treg that secrete inhibitory cytokines such as interleukin (IL)-10 and/or transforming growth factor (TGF)-ß. (more…)

Acute-Phase Response: The Innate Immune System

acute phase response
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…)

Complement Cascade: Antibodies and Phagocytic Cells to Clear Pathogens

complement cascade
An especially elaborate and important type of innate antimicrobial enzymes defense is provided by a group of serum proteins that together make up the complement cascade pathway. This group comprises more than two dozen different liver-and macrophage-derived proteins, called complement factors or components, most of which normally circulate in the form of proenzymes that have latent protease activity. As a rule, each of the proteases becomes active when proteolytically cleaved and will then catalyze cleavage and activation of a different complement component. (more…)

Peptide Antibiotics and Defensins Amino Acids

peptide antibiotics
Other humoral effectors and humoral factors have the ability to lyse microorganisms directly. The best studied of these are a class of small peptide antibiotics known as defensins, which in their active forms are all roughly 30 amino acids long (3,5 kilodaltons), positively charged, and protease-resistant. Each also has three internal disulfide bonds. They are classified as either α or β defensins based on the arrangement of the disulfides, but both classes have nearly the same compact, folded structure consisting of three strands of antiparallel β-pleated sheets. (more…)

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