Th2 Immune Responses Flashcards
Role of cytokines
- cell-to-cell signaling
- differentiation
- proliferation
- chemotaxis
- immunomodulation
- Ig isotype switching
Signature cytokine of Th1
IFN-y
Signature cytokines of Th2
IL4,5,13
Which cytokines are needed for Th2 differentiation?
IL2,4
Which cytokines are needed for Th1 differentiation
Il-4 neutralised
IL-12/IFN-y
Signature cytokines of Th17
Il-17a
IL-17F
IL-22
Transcription factors needed by Th2 cells
GATA2 (Il-4)
STAT5 (Il-2)
Role of Il-4
- induces isotype switching to IgE by B cells
- potentiates IgE production
- enhances IgE-mediated response by upregulating IgE receptors on inflam cells
- regulates Th2 cell differentiation
Role of Il-13
- produced by Th2 cells
- has 70% sequence homology with Il-4
- binds a heterodimer of Il-4Ra and Il-13Ra chains
- Il-4 and Il-13 have a degree of functional overlap
What does Il-13 induce?
- IgE production
- airway inflammation
- mucus hypersecretion
- eosinophilia
- upreg of VCAM-1
- smooth muscle contractility
- vascular permeabiltiy
Role of Il-5
Regulates most aspects of eosinophil behaviour:
- growth
- maturation
- differentiation
- survival
- activation
Effector cells of the innate immune system
macs neuts eosinophils mast cells basophils platelets NK cells complement
How are helminths killed?
Th2 effector cells such as mast cells and eosinophils release toxic granules that damage parasites
Which proteins are toxic to helminths?
Major basic protein
Eosinophil peroxidase
Eosinophil cationic protein
Define a hypersensitivity reaction
Harmful immune response to inherently harmless environmental antigens such as pollen, dust mites, food and drugs
What is allergic disease characterized by?
- IgE-dependent mechanisms
- Th2-type immune response
Principal characteristics of asthma
- reversible airflow obstruction
- hyperresponsiveness of the lungs to challenge with smooth muscle agonists
- chronic airway inflammation
Clinical symptoms of asthma
- enlarged smooth muscle cell layer
- narrowed bronchiole
- restricted airway with increased mucus production
- goblet cell hyperplasia
Pattern recognition receptors in allergic responses
- PAR (protease-activated receptor)
- TLR
- Dectin (recognises fungal pathogens)
What are ILCs?
A family of non-T, non-B effector cells that have conserved effector cell functions
Characteristics of ILCs
- belong to the lymphoid lineages
- lack rearranged antigen-specific receptors
- react quickly to a wide range of innate signals
- secrete high conc of cytokines
- localised to mucosal surfaces
