Immunology review LS6 2021
Lesson 1 The introduction
We want to obtain knowledge about:
● the physical and chemical barriers
● the innate immune system (complement
system, NK cells, and phagocytosis)
● the adaptive immune system (antigen
presentation, B- and T-cell development and
activation, antibodies)
→ All these components are coherent!
→ The physical/chemical barrier can be found at:
● the skin (commensals)
● the mucosa in the nose, mouth, etc.
● antimicrobial proteins (chemical)
● → Innate vs adaptive:
The innate immune response is aspecific as
they have a lot of receptors so they can
recognize a lot of pathogens, whereas the
adaptive immune system is very specific due to specific and fewer
receptors
● The innate immune system recognizes patterns and the adaptive
immune system recognizes antigens (specific again)
● The innate immune system takes action immediately and the adaptive
immune system takes a couple of days, like 4-5 days
● In the innate immune system, the initiation starts at the site of infection
whereas the adaptive immune system starts in specialized organs
(lymph nodes)
● The innate immune system will not have a stronger reaction at the
2ndencounter and the adaptive immune system goes by memory, so it
will recognize the same pathogen on the 2nd encounter
Macrophages, granulocytes, dendritic cells, macrophages, ILCs mast cells, and
NK-cells are present in the innate immune response
● A lymphoid progenitor cell (bone marrow) can become a T- or B-cell, an
NK cell, ILC, or an immature dendritic cell (blood)
● Myeloid progenitor(bone marrow) can become an immature dendritic
cell (blood), or a granulocyte/macrophage progenitor, or a
megakaryocyte/erythrocyte progenitor (bone marrow)
● The dendritic cell is the bridge between the innate and the adaptive
immune system!
,● In the lymph nodes, the B-cells can become plasma cells, the T-cells can
become activated T-cells, the NK cells can become activated NK-cells,
and as well for the ILC’s → they all become effector cells
● The immature dendritic cells can either become mature in the lymph
nodes, as well as for the immature dendritic cells found in the tissue
, ● Precursor mast cells in the blood can become mast cells in tissue and
monocytes in the blood can become macrophages
in the tissue
→ Cells in the innate immune system
● Neutrophils are present in the blood and are very
mobile, though they are short-lived (7 days). They
are very important for the quick 1st immune
response
● Basophils and eosinophils are both involved in
defense against parasitic and allergic responses
● Mast cells are involved in allergies, make sure
that wounds heal, immune tolerance so we
don’t respond to everything, and defense
against pathogens. They release granules
that contain histamine (dilates veins and
causes inflammation) and active agents
● NK-cells are cytotoxic cells, they can kill
virus-infected cells and cancer cells by their
granules which contain a lot of enzymes that
can destroy the cells.
● Phagocytes: the macrophage and dendritic
cell can phagocytose and present antigens
although the macrophage is better in
phagocytosis (lazy) whereas the dendritic cell
is better in presenting (salesman) → precursor
= monocyte)
, → Cells of the adaptive immune system
● B-cells/B lymphocytes can become plasma cells (secrete antibodies) or
memory cells after activation, so they will stay in the body
● T-cells/T lymphocytes can become CD4+ T-helper cells (help other
immune cells with their functionality), CD8+ cytotoxic T-cells (can kill
tumor cells and virally infected cells), or memory cells (both CD4/CD8)
→ Recognition
The immune system should be able to recognize self from non-self e.g.
commensals like E.coli found in the intestine, it is non-self but no reaction is
desired whereas cancer cells are own cells but they are dangerous so we want
a reaction to occur
→ Recognition of the innate immune system
● Signal recognition: PAMP
(pathogen-associated molecular patterns)
e.g. the flagella, viral RNA
● Danger recognition: DAMP
(danger-associated molecular patterns)
e.g. if there is a lot of free ATP → dying or
damaged cells
● The body uses pattern recognition
receptors (PRRs) found on the cell
membrane, in endosomes, or the cytosol
→ it is important to have only a restricted
amount but there are multiple different
receptors on one cell as opposed to T-cell
receptors and antibody does (only one
but present a lot)
● Each pathogen will activate different
combinations of receptors which will
cause a different kind of signaling pathway will be produced
Lesson 1 The introduction
We want to obtain knowledge about:
● the physical and chemical barriers
● the innate immune system (complement
system, NK cells, and phagocytosis)
● the adaptive immune system (antigen
presentation, B- and T-cell development and
activation, antibodies)
→ All these components are coherent!
→ The physical/chemical barrier can be found at:
● the skin (commensals)
● the mucosa in the nose, mouth, etc.
● antimicrobial proteins (chemical)
● → Innate vs adaptive:
The innate immune response is aspecific as
they have a lot of receptors so they can
recognize a lot of pathogens, whereas the
adaptive immune system is very specific due to specific and fewer
receptors
● The innate immune system recognizes patterns and the adaptive
immune system recognizes antigens (specific again)
● The innate immune system takes action immediately and the adaptive
immune system takes a couple of days, like 4-5 days
● In the innate immune system, the initiation starts at the site of infection
whereas the adaptive immune system starts in specialized organs
(lymph nodes)
● The innate immune system will not have a stronger reaction at the
2ndencounter and the adaptive immune system goes by memory, so it
will recognize the same pathogen on the 2nd encounter
Macrophages, granulocytes, dendritic cells, macrophages, ILCs mast cells, and
NK-cells are present in the innate immune response
● A lymphoid progenitor cell (bone marrow) can become a T- or B-cell, an
NK cell, ILC, or an immature dendritic cell (blood)
● Myeloid progenitor(bone marrow) can become an immature dendritic
cell (blood), or a granulocyte/macrophage progenitor, or a
megakaryocyte/erythrocyte progenitor (bone marrow)
● The dendritic cell is the bridge between the innate and the adaptive
immune system!
,● In the lymph nodes, the B-cells can become plasma cells, the T-cells can
become activated T-cells, the NK cells can become activated NK-cells,
and as well for the ILC’s → they all become effector cells
● The immature dendritic cells can either become mature in the lymph
nodes, as well as for the immature dendritic cells found in the tissue
, ● Precursor mast cells in the blood can become mast cells in tissue and
monocytes in the blood can become macrophages
in the tissue
→ Cells in the innate immune system
● Neutrophils are present in the blood and are very
mobile, though they are short-lived (7 days). They
are very important for the quick 1st immune
response
● Basophils and eosinophils are both involved in
defense against parasitic and allergic responses
● Mast cells are involved in allergies, make sure
that wounds heal, immune tolerance so we
don’t respond to everything, and defense
against pathogens. They release granules
that contain histamine (dilates veins and
causes inflammation) and active agents
● NK-cells are cytotoxic cells, they can kill
virus-infected cells and cancer cells by their
granules which contain a lot of enzymes that
can destroy the cells.
● Phagocytes: the macrophage and dendritic
cell can phagocytose and present antigens
although the macrophage is better in
phagocytosis (lazy) whereas the dendritic cell
is better in presenting (salesman) → precursor
= monocyte)
, → Cells of the adaptive immune system
● B-cells/B lymphocytes can become plasma cells (secrete antibodies) or
memory cells after activation, so they will stay in the body
● T-cells/T lymphocytes can become CD4+ T-helper cells (help other
immune cells with their functionality), CD8+ cytotoxic T-cells (can kill
tumor cells and virally infected cells), or memory cells (both CD4/CD8)
→ Recognition
The immune system should be able to recognize self from non-self e.g.
commensals like E.coli found in the intestine, it is non-self but no reaction is
desired whereas cancer cells are own cells but they are dangerous so we want
a reaction to occur
→ Recognition of the innate immune system
● Signal recognition: PAMP
(pathogen-associated molecular patterns)
e.g. the flagella, viral RNA
● Danger recognition: DAMP
(danger-associated molecular patterns)
e.g. if there is a lot of free ATP → dying or
damaged cells
● The body uses pattern recognition
receptors (PRRs) found on the cell
membrane, in endosomes, or the cytosol
→ it is important to have only a restricted
amount but there are multiple different
receptors on one cell as opposed to T-cell
receptors and antibody does (only one
but present a lot)
● Each pathogen will activate different
combinations of receptors which will
cause a different kind of signaling pathway will be produced
