Immunology Chapter 1 – elements of the immune system and their
roles in defense
Intro
Balancing the immune system (protects us against infectious diseases – has
memory):
Activation (inflammation)
Inhibition (tolerance)
Artificial induction of immunity:
Vaccination: very efficient for activation of the immune system – polio, ebola
Anti-tumor immunotherapy
Dysregulation of the immune system
Autoimmune disease: immune response against “self” (diabetes, MS, arthritis)
Allery: immune response against harmless molecules (pollen)
Transplant rejection
Cancer
The immune system recognizes and remember pathogens
Antigen: molecule or fragment of a pathogen recognized by lymphocytes of
the immune system
Epitope: the minimal part of an antigen, which is recognized
Chapter 1
2 immune systems
Innate immune system: rapid, a-specific, fixed (equal in everyone), present in tissues,
uses limited number of receptors, mediated by soluble molecules and immune cells,
practiced by limited amount of cell types and molecules, no-long term protection or
memory and constant during response.
Goal:
o Recognition pathogen
o Recruiting immune cells with eliminate pathogen
o Activation adaptive immune system
Lot of these cells has granules and this is important in killing bacteria
Dendritic cell: needed to activate the adaptive immune system. They are
presenting the antigen to T-cells.
Macrophages
Monocytes
Mast cell
Granulocytes: polymorphonuclear leukocytes
o Basophil
o Eosinophil
o Neutrophil
Natural killer (NK) cell
Innate immunity
, Recognition by innate immunity starts inflammation:
Healthy skin is not inflamed surface wound introduces bacteria. Bacteria can
bound to 2 kind of receptors on the macrophages
- Phagocytic receptor: the bacteria is engulfed into the macrophage and
degraded.
Bacterial cell surface induces cleavage and activation
of complement one complement fragment bind to
bacterium (enhanced phagocytosis by tagging
pathogen) the other attracts an effector cell (recruiting
effector cell) both complement fragments bind to
each other the effector cell engulf the bacterium kill
its and breaks it down
= complement activation
- Signalling receptor: this induces the synthesis of
inflammatory cytokines
because cells secrete cytokines there is vasodilation and
an increased vascular permeability allow inflammatory cells
to leave blood and enter tissue the infected tissue becomes inflamed causing
redness, swelling and pain
Neutrophils:
Neutrophils are reserved at the bone marrow and are released
when needed to fight. They enter the infected tissue where they
(together with macrophages) engulf and kill bacteria. The
neutrophils die in the tissue and are engulfed and degraded by
macrophages
Cytokines and chemokines:
Cytokines: induce cell division and activation
Chemokines: induce emigration
They are small soluble proteins which are secreted by cells
They can signal in an autocrine (same cell that secretes) and paracrine (other cell)
fashion
Immune cells recognize cytokines and chemokines vis receptors expressed on their
cell surface
Adaptive immune system: slow, specific, variable (different in every individual),
initiated in lymphoid tissues, long-term protection and memory and improve during
response
Lymphocytes
o B-cell
o T-cell
CD4+ T cell: help other immune cells
CD8+ T cell: kill infected cells
o Natural killer (NK) cell
Adaptive immunity
Response adds to an ongoing innate immune response:
roles in defense
Intro
Balancing the immune system (protects us against infectious diseases – has
memory):
Activation (inflammation)
Inhibition (tolerance)
Artificial induction of immunity:
Vaccination: very efficient for activation of the immune system – polio, ebola
Anti-tumor immunotherapy
Dysregulation of the immune system
Autoimmune disease: immune response against “self” (diabetes, MS, arthritis)
Allery: immune response against harmless molecules (pollen)
Transplant rejection
Cancer
The immune system recognizes and remember pathogens
Antigen: molecule or fragment of a pathogen recognized by lymphocytes of
the immune system
Epitope: the minimal part of an antigen, which is recognized
Chapter 1
2 immune systems
Innate immune system: rapid, a-specific, fixed (equal in everyone), present in tissues,
uses limited number of receptors, mediated by soluble molecules and immune cells,
practiced by limited amount of cell types and molecules, no-long term protection or
memory and constant during response.
Goal:
o Recognition pathogen
o Recruiting immune cells with eliminate pathogen
o Activation adaptive immune system
Lot of these cells has granules and this is important in killing bacteria
Dendritic cell: needed to activate the adaptive immune system. They are
presenting the antigen to T-cells.
Macrophages
Monocytes
Mast cell
Granulocytes: polymorphonuclear leukocytes
o Basophil
o Eosinophil
o Neutrophil
Natural killer (NK) cell
Innate immunity
, Recognition by innate immunity starts inflammation:
Healthy skin is not inflamed surface wound introduces bacteria. Bacteria can
bound to 2 kind of receptors on the macrophages
- Phagocytic receptor: the bacteria is engulfed into the macrophage and
degraded.
Bacterial cell surface induces cleavage and activation
of complement one complement fragment bind to
bacterium (enhanced phagocytosis by tagging
pathogen) the other attracts an effector cell (recruiting
effector cell) both complement fragments bind to
each other the effector cell engulf the bacterium kill
its and breaks it down
= complement activation
- Signalling receptor: this induces the synthesis of
inflammatory cytokines
because cells secrete cytokines there is vasodilation and
an increased vascular permeability allow inflammatory cells
to leave blood and enter tissue the infected tissue becomes inflamed causing
redness, swelling and pain
Neutrophils:
Neutrophils are reserved at the bone marrow and are released
when needed to fight. They enter the infected tissue where they
(together with macrophages) engulf and kill bacteria. The
neutrophils die in the tissue and are engulfed and degraded by
macrophages
Cytokines and chemokines:
Cytokines: induce cell division and activation
Chemokines: induce emigration
They are small soluble proteins which are secreted by cells
They can signal in an autocrine (same cell that secretes) and paracrine (other cell)
fashion
Immune cells recognize cytokines and chemokines vis receptors expressed on their
cell surface
Adaptive immune system: slow, specific, variable (different in every individual),
initiated in lymphoid tissues, long-term protection and memory and improve during
response
Lymphocytes
o B-cell
o T-cell
CD4+ T cell: help other immune cells
CD8+ T cell: kill infected cells
o Natural killer (NK) cell
Adaptive immunity
Response adds to an ongoing innate immune response:
