Flashcards in E-Learning Adaptive Immune System Deck (20)
What are the 2 types of adaptive immunity?
Cell-mediated - T cells
Humoral - Abs from B cells
Overall what do Th cells do?
Respond to MHC2 on APCs:
- Cytokine release
- B cell Ab class switching
- Growth/activation of Tc Cells
- Maximise phagocyte activity
What do Th1 cells specifically do?
Target intracellular pathogens and cellular immunity through IFN-gamma
What do Th2 cells do specifically?
Target extracellular pathogens and help in humoral immunity & allergy through IL-4,5,13
What do Th17 cells do?
Involved in inflammation and target extracellular pathogens though IL-17,21,22
What can CD8 T cells do?
1) Release Anti-tumour/viral IFN & TNFalpha
2) Release perforin & granzymes --> Apoptosis
3) Release FasL --> Apoptosis
What do Treg cells do?
Suppress immune response and inflammation by IL-10 & TGF-beta
We have T cells with a wide variety of TCR binding sites so we can recognise lots of pathogenic antigens. How does this occur?
During maturation in the thymus T cells undergo VDJ recombination --> Varied TCRs
Where do naïve T cells differentiate into Th or Tc cells?
Secondary Lymphoid Organs once presented with their complementary Antigens
How do we end up with highly varied BCR binding sites?
By VDJ recombination during maturation of B cells in the bone marrow
How can B cells be activated?
1) T cell dependant
2) T cell independent (antigens in secondary lymphoid organs)
3) Memory B cell Activation
What happens to B cells after activation?
1) Become short lived plasma cells that produce IgM or IgG
2) Undergo class switching in germinal centres --> becoming long-lived plasma cells or Memory B cells
Describe the structure of an antibody?
The trunk or FC region is constant. this is what communicates with other immune cells and is all heavy chain
The stalks or FAB region are variable, they bind to antigens
Most Immunoglobulins are monomers, which aren't?
IgM is a pentamer
IgA is a Dimer
Which Abs are produced in immune response to pathogens?
IgM first then IgG
Which Ab can cross the placenta?
Which Ab targets parasites and is involved in allergy?
What can Abs do?
1) Form Ab-Ag complexes
2) Opsonise for phagocytes
3) Activate complement (classical pathway)4) Ab mediated Cellular Cytotoxicity
How does Ab production change after the 1st exposure?
In the first exposure you get a lag, then IgM spike then IgG spike
In 2nd exposure the IgM comes quicker and lower, then the IgG spikes higher and for much longer