Pathophysiology of the immune system

Question 1

5 clinical signs of an infection

Answer 1

calor
rubor (red)
tumor (swelling)
dolor
functio laesa (reduced function)

Question 2

what are cytokines ?

Answer 2

signals to communicate with other cells

Question 3

what is pus ? when ?

Answer 3

product of dead cells and dead bacteria -> happens if there is a bacterial infection

Question 4

what does the innate immune system do (3 things) and why do we need more ?

Answer 4

1) eliminates / kills pathogens or tumor cells
2) recognizes damaged cells
3) recognizes pathogen specific patterns (PAMPs)

But :
- starts every time from scratch
- some pathogens avoid being eaten (capsule)

Question 5

BCR VS TCR : where mainly ? Diversity ? two regions ?

Answer 5

• mainly in lymph nodes, very little in blood
• each receptor is unique
• variable region for antigen specifity and constant region that gives signaling

Question 6

which signal is very important to determine which antibody is produced ?

Answer 6

The signal that the T helper cells give to the B cells

Question 7

4 antibody isotypes, short description and %

Answer 7

1) IgG : 2nd response -> stay for a long time, passive immunity (placenta), most frequent (75%)
2) IgM : 1st response -> can be measured if infection recent or on-going, 10%
3) IgA : mucus, saliva, …
4) IgE : histamine release, very minor fraction

Question 8

Common variable immunodeficiency ? 3 consequences

Answer 8

Defect in B cell maturation :
- lack of IgG
- prone to infections
- frequent autoimmune diseases

Question 9

3 main vaccination concepts

Answer 9

1) Passive : provide antibodies against cell entry receptors ( ex : attach to spike protein of sars) -> doesn’t last long

2) Live attenuated : lasts forever, acivates all cells, low cost, BUT complications if immunodeficient, strict conditions of storage

3) Protein : only vaccinate with a recombinant protein (ex surface antigen), but booster required

Question 10

problem with polysaccharides, and how you solve it ?

Answer 10

Polysaccharides are only recognized by B cells and not T cells -> bind a protein to the polysaccharide so that T cells recognize it too -> better immune response

Question 11

mRNA and vector vaccines (how it works, + and -)

Answer 11

1) mRNA : introduce the RNA (in lysosome) that codes for the spike protein into the cells -> we will then form antibodies.
+ : impossible to integrate in DNA and rapidly degraded

2) vector : put spike gene in vector virus DNA (doesn’t cause disease in humans) and introduce into our cells.
Problem : we can develop vector immunity -> vaccine doesn’t work anymore

Question 12

two types of allergies, what causes symptoms ? solution ?

Answer 12

1) acute (IL-4)
2) delayed (IFNg)

IgE activates mast cells -> release histamine -> mucus and vasoconstriction.

We can use antihistaminics

Question 13

give an example of autoimmmune disease, what can be used as a diagnostic factor ?

Answer 13

rheumatoid arthritis -> joint and bone destruction as a consequence of inflammation.

Autoantibodies are a diagnostic factor

Question 14

treatment of autoimmunity ? explain what biologics are and what they do

Answer 14

Immunosuppression

Biologics are drugs extracted from biological sources -> mainly monoclonal antibodies to block cytokines or cells.

Question 15

what do CD8 T cells do ? how do they recognize the cells ?

Answer 15

They kill cancer and virus infected cells.
We have a HLA (MHC) on every cell -> presents peptide. If virus or cancer peptide, CD8 T cell attacks.

Question 16

3 cancer immunophenotypes, immunotherapy (2) ?

Answer 16

Preexisting immunity, excluded infiltrate, immunologically ignorant.

Enhance immune cells with checkpoint inhibitors (make them stronger)
Add immune cells :
- tumor infiltrating lymphocytes (TIL) expansion
- CAR-T : modify T cells so that they recognize the cancer