Theme 1 Intro
Immunology: biological and medical aspects
Biological
● Cell-cell interactions and communication
● Cell proliferation and (programmed) cell death
● Activation of cells via receptors and signal transduction
Medical
● Diseases due to a failing immune system:
○ immunodeficiencies (e.g. AIDS)
○ allergic reactions (hypersensitivity reactions)
○ autoimmune diseases
● Health by manipulating the immune system:
○ vaccination against infectious diseases
○ immunotherapy against cancer
○ immunosuppression after organ transplantation
Innate and acquired (adaptive) immunity
Innate Immune system Acquired (adaptive) Immune system
● Cellular ● Cellular
○ Macrophages ○ T lymphocytes
○ Granulocytes ○ B lymphocytes
● Humoral ● Humoral
○ Complement ○ Antibodies
○ Cytokines ○ Cytokine
1
,Immune response: 3 different phases
Recognition phase
● How is the antigen recognized?
● How does the structural diversity of receptors arise?
● How is it distinguished between self and non-self?
Induction phase
● Induction of an immune response or tolerance?
● Which type of response?
Effector phase
● How do the effector mechanisms operate?
● How is an immune response terminated?
● How is memory established and maintained?
Antigen receptors of B and T lymphocytes
Two signals required for activation of naive lymphocytes
1. Signal 1 by recognition of antigen
2. Second signal (co-stimulation, cytokines)
Activation leads to:
● Proliferation (clonal expansion)
● Differentiation
● Biological effect
2
,3
, Theme 2 Innate Immunity
Function of the innate immune system
● Prevents, controls or eliminates invading microbes
● Elimination of damaged cells and initiation of the process of tissue repair
● Activation of the adaptive immune system
Components of the innate immune system
Patrolling cells: attack pathogens, but don’t remember for the next time
Innate immune receptors: recognizes features common to many pathogens
Proteins: Complement, acute phase proteins and cytokines
● Phagocytes (cells) (e.g., macrophages, DC)
● Innate immune receptors
● Complement proteins
● Cytokines
● Natural killer (NK) cells
Macrophages and neutrophils can engulf and
digest bacteria →
But how does the body recognise what is a pathogen?
PAMPs
● Shared by a large group of pathogens (general
patterns & non-specific)
● Conserved and not subject to antigenic
variability
● Pathogens cannot change them because they
are essential for the survival or pathogenicity
● Distinct from self-antigens
PAMPs are parts of the
pathogen that receptors in
the body can recognise.
These are things these
pathogens need to survive,
like DNA, flagella or certain proteins. These aren’t variable. They
are always the same and there for easy to recognise with PRRs.
4
Immunology: biological and medical aspects
Biological
● Cell-cell interactions and communication
● Cell proliferation and (programmed) cell death
● Activation of cells via receptors and signal transduction
Medical
● Diseases due to a failing immune system:
○ immunodeficiencies (e.g. AIDS)
○ allergic reactions (hypersensitivity reactions)
○ autoimmune diseases
● Health by manipulating the immune system:
○ vaccination against infectious diseases
○ immunotherapy against cancer
○ immunosuppression after organ transplantation
Innate and acquired (adaptive) immunity
Innate Immune system Acquired (adaptive) Immune system
● Cellular ● Cellular
○ Macrophages ○ T lymphocytes
○ Granulocytes ○ B lymphocytes
● Humoral ● Humoral
○ Complement ○ Antibodies
○ Cytokines ○ Cytokine
1
,Immune response: 3 different phases
Recognition phase
● How is the antigen recognized?
● How does the structural diversity of receptors arise?
● How is it distinguished between self and non-self?
Induction phase
● Induction of an immune response or tolerance?
● Which type of response?
Effector phase
● How do the effector mechanisms operate?
● How is an immune response terminated?
● How is memory established and maintained?
Antigen receptors of B and T lymphocytes
Two signals required for activation of naive lymphocytes
1. Signal 1 by recognition of antigen
2. Second signal (co-stimulation, cytokines)
Activation leads to:
● Proliferation (clonal expansion)
● Differentiation
● Biological effect
2
,3
, Theme 2 Innate Immunity
Function of the innate immune system
● Prevents, controls or eliminates invading microbes
● Elimination of damaged cells and initiation of the process of tissue repair
● Activation of the adaptive immune system
Components of the innate immune system
Patrolling cells: attack pathogens, but don’t remember for the next time
Innate immune receptors: recognizes features common to many pathogens
Proteins: Complement, acute phase proteins and cytokines
● Phagocytes (cells) (e.g., macrophages, DC)
● Innate immune receptors
● Complement proteins
● Cytokines
● Natural killer (NK) cells
Macrophages and neutrophils can engulf and
digest bacteria →
But how does the body recognise what is a pathogen?
PAMPs
● Shared by a large group of pathogens (general
patterns & non-specific)
● Conserved and not subject to antigenic
variability
● Pathogens cannot change them because they
are essential for the survival or pathogenicity
● Distinct from self-antigens
PAMPs are parts of the
pathogen that receptors in
the body can recognise.
These are things these
pathogens need to survive,
like DNA, flagella or certain proteins. These aren’t variable. They
are always the same and there for easy to recognise with PRRs.
4
