Chronic Inflammatory Diseases Flashcards
What is inflammation?
The biological process in which the immune system respond to an insult.
What are the characteristics of inflammation?
Redness
Heat
Swelling
Pain
Dysfunction
What is acute inflammation?
Transient as the insult is cleared and tissues heal
What is chronic inflammation?
Gets worse leading to loss of tissue, fibrosis and comorbidities.
Chronic pain and behavioural disorders
Reduce quality of life
What simulates innate immune cells?
Pathogen (PAMP) or Damage (DMAP) associated molecular patterns.
What are Pattern Recognition Receptors (PRR)?
Expressed by immune cells.
Recognise PAMP and DAMP
Mediate inflammatory signalling
Early warning system
What are cytokines?
Critical factors mediating inflammatory responses.
Where does early inflammation begin?
insults induce Langerhans cells migration to draining lymph nodes.
What is the function of cytokines and growth/differentiation factors in inflammation?
Activate skin resident immune cells.
What is the role of chemokines (CCL) in inflammation?
Attract macrophage, monocytes, neutrophils and T cells from the blood.
Briefly describe the process of innate immune sensing and signalling?
Sensors detect signals inside and outside
Sensors activate signalling pathways (adaptor)
These then stimulate transcription of cytokine gene infernos (IFNs).
They have an effect through IFN stimulated genes (ISGs).
Outline he assembly of the inflammasome.
- Signal is detected (PAMP) or (DMAP).
- PRR, known as NOD-like receptors undergo a conformational change exposing a binding site.
- NLRs recruit an adaptor protein called Apoptosis- related ASC which contains CARD, caspase recruitment domain.
- Form the ASC filament, scaffolding for the assembly of the inflammasome.
- Procaspase-1 undergoes self cleavage leading to caspase-1.
- It then cleaves proinflammatory cytokines.
- Active cytokines are released from the cell triggering an inflammatory response which recruits immune cells to the site.
What is a mast cell?
Immune cells which have a role in allergic reactions.
Allergen binds to antibodies on the surface of mast cells which release inflammatory substances.
What kinds of things are mast cell activators?
Receptor-binding agonists
Physical activators
Cell-cell contact
What kinds of things are mast cell molecules?
Preformed mediators
T and B cells
Newly synthesized mediators
What is the role of adjuvants?
Induce innate immune cells to mature and make cytokines artificially by mimicking PAMP and DAMP.
Why are adjuvants used?
Adjuvants are used in vaccines to enhance the body’s immune response.
What are dendric cells (DCs)?
Specialized to provide critical signals that activate naïve (resting) T cells.
How do DCs and T cells interact?
Form innate cell-cell associations
DCs provide 3 key signals. What are they?
Antigen
Co-stimulation
Cytokines
What is the antigen signal?
Presented as peptides bound to MHC recognized by the T cell receptor (TCR).
What is the co-stimulation signal?
CD80/86 recognized by CD28 on T cells
What is the cytokines signal?
Activating cytokines such as IL-12
What is CD28?
CD28 is like a key on the surface of T cells that helps activate them when they encounter invaders, boosting the immune response.
What is IL-12?
Promotes the differentiation of T cells.
Stimulates the production of cytokines
Enhances natural killer cells.
What happens to T cells once they are activated?
Once activated, T cells proliferate rapidly & differentiate to become cytotoxic (CTL) or helper (TH) T cells (effector T cells)
What are the key features of Antigen Presenting Cells (APCs)?
The ability to capture antigens.
They can express the MHC
They express co-stimulatory molecules
Initiate the adaptive immune response
Why are APC:T cell interactions selective?
Specific antigen recognition
Co-stimulatory signals
Regulatory mechanisms
Tissue microenvironment
What is the MHC?
The Major Histocompatibility Complex (MHC) is a set of genes that encode proteins responsible for presenting antigens to T cells, crucial for the immune system’s recognition of foreign substances.