Reviewer: S. Randhawa, M.D., Allergist/Immunologist and Assistant Professor at LSU (Shreveport) Department of Allergy and Immunology
Source: T cells (TH1, CD8+ T cells), NK cells
- Macrophages: activation (increased microbicidal functions)
- B cells: isotype switching to opsonizing and complement-fixing IgG subclasses
- T cells: TH1 differentiation
- Various cells: increased expression of class I and class II MHC molecules, increased antigen processing and presentation to T cells
Interferon-gamma suppresses TH2-cell-mediated allergic inflammation and suppresses allergic airway inflammation in animal models. It is induced during SCIT.
What is T-bet?
T-bet (also called TBX21 or T-box 21) is pivotal for Th1 maturation. STAT4 activates the transcription factor T-bet, which induces the secretion of IFN-gamma. T-bet promotes Th1 development by direct induction of IFN-gamma and IL-12Rbeta2 chain gene transcription. IFN-gamma acts an amplifier by binding to its receptor on Th1 cells and activating STAT1, which then engages T-bet. T-bet is a bridge between innate and adaptive immunity (http://buff.ly/1aD6h8s).
T-bet inhibits IL-4, IL-5, and IL-17 secretion. T-bet may also inhibit Th2 differentiation by preventing GATA3 from interacting with its target DNA.
Potential treatment targets
T-bet: CpG antisense oligodeoxynucleotides
GATA3: GATA3-specific DNAzyme and CpG antisense oligodeoxynucleotides
Interferon-gamma therapy in asthma
Early studies of recombinant human IFN gamma gamma SQ in asthma were disappointing. One small study showed a reversal of the TH2-cell cytokine profile in severe asthma.
IFN beta therapy in asthma
Epithelial cells from asthmatics have an impaired protective IFNb response to infection with the common cold virus. Trials of recombinant human IFNb by inhalation to prevent severe virus-induced asthma exacerbations.
What is IGRA?
Interferon Gamma Release Assay (IGRA): used in any evaluation for TB infection (active or latent). It is more specific than TSTs (PPD), which may be positive with previous BCG or exposure to non-TB Mb. A positive test indicates TB infection. A negative test excludes TB in immunocompetent patients.
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BCG vaccination: 90 years on and still so much to learn - Thorax http://goo.gl/2tyRj
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