1. Introduction Flashcards
Major functions of the immune system
Protection of our body from “parasites”
What is Microbiota?
the flora that lives within our body, which consists of many different microbial communities.
What is an „Extended self”?
a multicellular organ, which consumes, stores and redistributes energy derived from food.
What is Interstitial fluid?
more fluid leaves the circulation on the arteriosus side of the capillary system than what is drained by the venous side
What are the Five main features of the immune response?
- Antigen specificity
- Ag-sensitivity
- Memory
- Operation based on clone
- Immune homeostatsis
Five main features of the immune response - Antigen specificity
-> What is an antigen?
any molecule or cell that elicits an immune response
Five main features of the immune response - Antigen specificity
-> What is an determinant?
Antigen determinant = epitope, a particular part of the antigen that is recognized by a T or B cell receptor
Difference between B & T cells?
They differ in Antigen recognition
What do T cells recognize?
Linear peptide sequences in the peptide binding groove of HLA (MHC) molecules
Five main features of the immune response - Antigen sensitivity
-> What make the antigen sensitivity?
Exponential amplification
-> One cell has one type of Ag receptor
Five main features of the immune response
-> What makes the feature “memory” important?
Efficient protection upon repeated exposure to infectious agents (T & B memory cells)
Five main features of the immune response
-> The operation is based on clone selection
-> What does it mean?
Five main features of the immune response
-> how can our body maintain immune homeostasis?
- Fast reaction when in danger
- Re-establishing homeostasis once the threat is over
Five main features of the immune response
-> Is the immune process reversible?
Yes, they are
Five main features of the immune response
-> What happen to immune homeostasis if there is an infection?
Five main features of the immune response - IMMUNE HOMEOSTASIS
-> 3 examples of regulatory cells?
Treg, Breg, iDC
Five main features of the immune response - IMMUNE HOMEOSTASIS
-> 4 examples of effector cells?
Th1, TH17, B, mDC
2 concepts of immunity
Innate immunity - immediate response
Adaptive immunity - develops in 1 - 2 weeks
How fast does innate immunity response when exposing to an infection?
Immediate response
How fast does innate immunity response when exposing to an infection?
Immediate response
How fast does ADAPTIVE immunity response when exposing to an infection?
in 1-2 weeks
List the cells involving in innate immunity
List the cells involving in adaptive immunity
Barriers of innate immunity
skin,
mucosal membrane,
secretions
Molecules of innate immunity
complement system, natural autoantibodies
8 Cells of the innate immunity
2 types of responses in adaptive immunity
Cellular (T)
Humoral (T)
Cells involving in adaptive immunity
Characteristics of Innate immunity
(Memory, Receptor specificity, amplification, latency, cells)
- Limited memory
- Limited receptor specificity
- Linear amplification
- No latency
- Macrophages, granulocytes, mast cells, dendritc cells (DCs), innate lymphoid cells (ILCs), NK cells, complement system, natural autoantibodies
Characteristics of ADAPTIVE immunity
(Memory, Receptor specificity, amplification, latency, cells)
- memory
- high specificity
- exponential amplification
- latency (1-2 weeks)
- T & B cells, antibodies
Adaptive immunity
TB
What type of immunity is lacking here (1, 2)?
1 - Lacking innate immunity only
2 - Lacking adaptive immunity only
What are the 2 types of immune organs?
Primary (central)
Secondary (peripheral)
What are the 2 Primary (central) immune organs?
1/ Thymus
2/ Bone marrow
4 types of Secondary (peripheral) immune organs
- Lymph nodes
- Spleen
- MALT (mucosal associated lymphatic tissue)
- SIS (skin immune system)
Organs involving in Adaptive immunity
- Bone marrow
- Thymus
- Peripheral immune organs
Where will recirculating lymphocytes organ?
In the lymph node, lymphocytes are searching for their ___
epitopes
If a recirculating lymphocyte encounters its antigen in a secondary immune organ…
-> What will happen?
it stops migrating, gets activated, proliferates and differentiates
If a recirculating lymphocyte encounters its antigen in a secondary immune organ…
-> What will happen?
it stops migrating, gets activated, proliferates and differentiates
Characteristics of primary immune response (time, amplitude, immunoglobulin)
- slower (longer latency)
- lower amplitudo
- predominatly IgM
Characteristics of secondary immune response (time, amplitude, immunoglobulin)
- faster (shorter latency)
- higher amplitudo
- predominantly IgG
What are cytokines? Their role?
Small, soluble proteins or glycoproteins (~5–20 kDa), which function as messengers or regulatory molecules.
4 types of communication in the immune system
- Juxtacrine
- Paracrine
- Autocrine
- Endocrine
The range of cytokine effects
-> Identify 1 & 2
1/ Paracrine signalling
2/ Autocrine signaling
Shared features of the cytokines
- They act via membrane receptors (relatively few high affinity receptors)
- Their effects are often transient (short lived mRNA and negative feedback)
9 pleiotropic effects of IL-6
5 important types of cytokines
- Organokines
- Adipokines
- Myokines
- Osteokines
- Hepatokines
Cytokines which are Pro-inflammatory
Cytokines which are Anti-inflammatory
What is cytokine storm? (also cytosine release syndrome)
A life threatening systemic inflammatory disease with highly elevated cytokine levels and hyperactivation of immune cells. It can be triggered by several pathogens, tumors and autoimmune diseases.
3 chemokine families
What is the relationship of sleep and immunity? (adrenergic tone, adaptive immunity)
Which simple method can be used to study the functions of the immune system?
Simple blood test (analysis of blood cells)
What can be the consequence of the absence of particular immune organs (because of a lesion or surgical removal)?
What happens if the bone marrow does not function?
- Thereisnoconsequenceatall
- There is a drop in the number of circulating blood cells (pancytopenia) with extensive and
recurrent infections - The thymus compensates for the functions of the bone marrow, only the B cell number
drops - The MALT compensates for the missing functions except for the red blood cell formation
- Autoimmune diseases may develop
There is a drop in the number of circulating blood cells (pancytopenia) with extensive and
recurrent infections
What happens in the thymus of an infants is removed surguvcally (e.g. during cardiac surgery)?
- The will be no consequence at all
- It will result in a condition that is not compatible with life
(necessitates thymus transplantation) - It may influence the peripheral T cell populations and may
result in premature immune aging - It may predispose for allergic diseases
- It may predispose for overweight
It may influence the peripheral T cell populations and may
result in premature immune aging
What can be the consequence of the removal of a lymph node?
- There will be no consequence at all
- The immune defense of the body will be reduced,
immunodeficiency develops - Recurrent, severe infections
- Lymhodema may develop because of the defective lymphatic
drainage - Predisposition for allergy
- Lymhodema may develop because of the defective lymphatic
drainage
What is a sentinel lymph node?
The sentinel lymph node is the primary filter in the way of the lymph drainage from a tumor. Its histological composition (after surgical removal) is an important indicator of the regional status of a tumor.
If a sentinel lymph node is metastasis-free, a formal block dissection (removal of all lymph nodes draining from the area of a given tumor) can be avoided.
What can be the consequence of the removal of the spleen?
- There will be no consequence at all
- Predisposition to infections
- Predisposition to infections by encapsulated bacteria, because of
the lack of memory cells - Predisposition to infections with intracellular pathogens
- Appendicitis may develop
- Predisposition to infections by encapsulated bacteria, because of
the lack of memory cells
What can be the consequence of the removal of tonsils?
- It has no immediate consequence
- Predisposition to viral infections
- Predisposition to infections by encapsulated bacteria
- Predisposition to infections by intracellular pathogens
- In the long run, predisposition for appendicitis
- It has no immediate consequence
Approximately what percentage of recirculating lymphocytes reacts with a given antigen?
a. < 0.01%
b. >1%
c. > 5%
d. ~ 0%
a. < 0.01%
Which are the shared and unique features of the immune and the central nervous systems?
- Their complexity is approximately the same
- Network-based operation
- Synapse formation
- Memory
- Cognitive functions
How does the number of immune cells (~ 2×1012 ) compare to the number of other cells in the human body?
They are comparable to the number of cells in the liver and the brain
Do granulocytes recirculate (similarly to lymphocytes)?
Yes, in average they spend 20 hours in the circulation.
However, they can only quit the circulation, they cannot reenter.
Very few lymphocytes migrate to the skin, brain of synovial membrane. How can they still enter these sites during inflammation?
Transiently, postcapillary venules transform to HEVs in these sites during inflammation
The primary immune response is followed by ___
a faster, stronger secondary response
For immune homeostasis, ____ are required
cells and molecules of opposing functions
The primary immune organs (BM and thymus) are the birth- and maturation places of ____ (2 types of cells), respectively
T and B cells
