Immunology
Theme 1
Immunology: biological and medical aspects
Biological
- Cell-cell interaction and communication
- Cell proliferation and (programmed) cell death
- Activation of cells via receptors and signal transduction
Medical
- Diseases due to a failing immune system
o Immunodeficiencies (e.g., AIDS)
o Allergic reactions (hypersensitivity reactions)
o Autoimmune diseases
- Health by manipulating the immune system
o Vaccination against infectious diseases
o Immunotherapy against cancer
o Immunosuppression after organ transplantation
Immune cells
- NK cells:
o Enzymes that make holes in the membrane of target cells and that induce apoptosis
and the production of cytokines
o Killing of virus-infected cells and tumor cells and instructing the adaptive immune
system
- Basophils:
o Secretion of Th2 cytokines, anticoagulant substances (heparin), and vasodilation
mediators (histamine)
o Activating the adaptive immune response (Th2), plays a role in allergic reactions
together with mast cells
- Neutrophils:
o Phagocytosis, lytic enzymes
o Removing pathogens by phagocytosis
- Eosinophils:
o Release granules containing toxic proteins and lytic enzymes after activation,
o Kills helminths and other intestinal pathogens directly
- Macrophages:
o Phagocytosis and production of chemokines and cytokines
o Activating local defenses and inducing inflammation
- Mast cell:
o Secretion of Th2 cytokines, anticoagulant substances (heparin), and vasodilation
mediators (histamine)
o Defense against parasites
- Dendritic cell:
o Phagocytosis and antigen presentation (with co-stimulation)
o Picking up antigens and presenting them to T-cells in the lymph nodes
1
,Innate and acquired (adaptive)
immunity
Innate immune system
- Cellular: macrophages,
granulocytes
- Humoral: complement,
cytokines
Adaptive immune system
- Cellular: T lymphocytes, B
lymphocytes
- Humoral: antibodies,
cytokines
2
,Immune response: 3 different phases
Recognition phase
- How is the antigen recognized?
- How does the structural diversity of receptors arise?
- How is distinguished between self and non-self?
Induction phase
- Induction of an immune response or tolerance?
- Which type of immune 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
Clonal selection of lymphocytes
Each antigen (X) selects a pre-existing clone of
specific lymphocytes and stimulates the
proliferation and differentiation of that clone.
Happens in B and T cells.
3
, Naïve lymphocytes become effector lymphocytes
Naïve lymphocytes express antigen
receptors but have not responded to
antigen.
Two signals required for activation of
naïve lymphocytes
1. Signal 1 by recognition of antigen
2. Second signal (costimulation,
cytokines)
Activation leads to:
- Proliferation (clonal expansion)
- Differentiation
- Biological effect
Trafficking of B and T lymphocytes from primary lymphoid organs to secondary lymphoid organs
Induction phase part I: antigens activate mature naïve lymphocytes
4
Theme 1
Immunology: biological and medical aspects
Biological
- Cell-cell interaction and communication
- Cell proliferation and (programmed) cell death
- Activation of cells via receptors and signal transduction
Medical
- Diseases due to a failing immune system
o Immunodeficiencies (e.g., AIDS)
o Allergic reactions (hypersensitivity reactions)
o Autoimmune diseases
- Health by manipulating the immune system
o Vaccination against infectious diseases
o Immunotherapy against cancer
o Immunosuppression after organ transplantation
Immune cells
- NK cells:
o Enzymes that make holes in the membrane of target cells and that induce apoptosis
and the production of cytokines
o Killing of virus-infected cells and tumor cells and instructing the adaptive immune
system
- Basophils:
o Secretion of Th2 cytokines, anticoagulant substances (heparin), and vasodilation
mediators (histamine)
o Activating the adaptive immune response (Th2), plays a role in allergic reactions
together with mast cells
- Neutrophils:
o Phagocytosis, lytic enzymes
o Removing pathogens by phagocytosis
- Eosinophils:
o Release granules containing toxic proteins and lytic enzymes after activation,
o Kills helminths and other intestinal pathogens directly
- Macrophages:
o Phagocytosis and production of chemokines and cytokines
o Activating local defenses and inducing inflammation
- Mast cell:
o Secretion of Th2 cytokines, anticoagulant substances (heparin), and vasodilation
mediators (histamine)
o Defense against parasites
- Dendritic cell:
o Phagocytosis and antigen presentation (with co-stimulation)
o Picking up antigens and presenting them to T-cells in the lymph nodes
1
,Innate and acquired (adaptive)
immunity
Innate immune system
- Cellular: macrophages,
granulocytes
- Humoral: complement,
cytokines
Adaptive immune system
- Cellular: T lymphocytes, B
lymphocytes
- Humoral: antibodies,
cytokines
2
,Immune response: 3 different phases
Recognition phase
- How is the antigen recognized?
- How does the structural diversity of receptors arise?
- How is distinguished between self and non-self?
Induction phase
- Induction of an immune response or tolerance?
- Which type of immune 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
Clonal selection of lymphocytes
Each antigen (X) selects a pre-existing clone of
specific lymphocytes and stimulates the
proliferation and differentiation of that clone.
Happens in B and T cells.
3
, Naïve lymphocytes become effector lymphocytes
Naïve lymphocytes express antigen
receptors but have not responded to
antigen.
Two signals required for activation of
naïve lymphocytes
1. Signal 1 by recognition of antigen
2. Second signal (costimulation,
cytokines)
Activation leads to:
- Proliferation (clonal expansion)
- Differentiation
- Biological effect
Trafficking of B and T lymphocytes from primary lymphoid organs to secondary lymphoid organs
Induction phase part I: antigens activate mature naïve lymphocytes
4
