Advanced immunology Flashcards
Lectures: -Week 3, day 4, lecture 1: Advanced lectures - Innate lymphocytes -Week 3, day 4, lecture 2: Advanced lectures - NK-cells -Week 3, day 4, lecture 3: Advanced lectures - Regulatory T-cells (76 cards)
Which 3 important B- and T-cell interactions take place in the lymph node?
- TCR <-> MHCII
- C40 <-> CD40L
- Cytokines
What additional signal do T-cells give to B-cells which have been activated through their BCR?
CD40/CD40L
Which mechanisms allow B-cells to be activated independent of T-cells?
- Crosslinking of BCR’s by repetitive antigens
- TLR’s
- BAFF
What is the difference between a T-cell dependent and T-cell independent response?
- A T-cell dependent B-cell response leads to
-Extrafollicular response: the formation of plasma cells that produce IgM
-B-cells that undero the germinal centre reaction, resulting in B-cells with a higher affinity:
–Non-IgM plasma cells (class switch)
–Memory B-cells - A T-cell independent B-cell response solely leads to the formation of IgM-producing plasma cells, without affinity maturation, class switch recombination or formation of memory B-cells
What is the approximate response time of an adaptive B-cell response?
~10 days
Which types of innate-like lymphocytes can be identified? (4)
- NK T-cells
- B1-cells
- γδ-T cells
- Marginal zone B-cells
Where do innate-like lymphocytes typically occur?
Anatomical locations contacting the outside world, such as mucosal surfaces and the pleural & peritoneal cavity
What is special about the TCR/BCR repertoire of innate-like lymphocytes?
They have a very limited receptor repertoire
Do innate-like lymphocytes have TCR/BCR’s?
Yes, but with a limited diversity
Why can innate-like B-cells always respond independent of T-cells?
They are present in a pre-activated state, only requiring BCR activation to become active
Which types of innate lymphoid cells can be identified? (4)
- ILC1
- ILC2
- ILC3
- NK-cells
Where do innate lymphoid cells typically occur?
Anatomical locations contacting the outside world, such as mucosal surfaces and the skin
Do innate lymphoid cells have a TCR/BCR?
No, they don’t
How are innate lymphoid cells activated?
By cytokines in their surrounding
Which two types of innate-like B-cells can be identified?
- Marginal zone B-cells
- B1-cells
Where do B1-cells occur?
In the peritoneum and pleural cavity
Where do marginal zone B-cells reside? Why is this location advantageous?
In the marginal zone of follicles in the white pulp in the spleen; this location is advantageous because they directly contact blood flowing along the follicles in sinuses, allowing them to rapidly respond to sepsis
How are marginal zone B-cells activated?
Marginal B-cells are already pre-activated and require relatively little stimulation; this stimulation is provided by repetitive patterns on bacterial antigens encountered during sepsis
Which type of antibody is produced by marginal zone B-cells, and why?
IgM, because these cells never undergo a germinal centre reaction and thus never undergo class switch recombination
What are natural antibodies?
Natural antibodies are a ‘first line of defence’, produced by B1-cells without prior experience to antigens
What is an important example of natural antibodies, and why?
Blood group antibodies, because they prevent blood transfusion to persons with a different blood group
What kind of groups are natural antibodies targeted at? Why is this advantageous?
Non-protein antigens such as glycolipids & carbohydrates; these are often found on bacteria
How are B1-cells selected? How does this help them in their function?
They are selected on the basis of low-level autoreactivity; this is not harmful to the body, but does cause them to continuously produce antibodies
True or false: in a healthy individual, antibodies produced by ‘regular B-cells’ (non-B1) are in the majority
False; in a healthy individual, the continuous production of antibodies by B1-cells is responsible for the majority of the antibodies in the serum
