Immunology summary
1
,Chapter 1 | Elements of the immune system and their roles in defense 3
Chapter 2 | Immediate response to infection: complement 7
Chapter 3 | Innate immunity: the induced response to infection 9
Chapter 4 | Antibody structure & BCR diversity 14
Chapter 5 | Antigen recognition by T lymphocytes 19
Chapter 6 | The development of B lymphocytes 24
Chapter 7 | The development of T lymphocytes 29
Chapter 8 | T cell mediated immunity 32
Chapter 9 | B cell mediated immunity 36
Chapter 10 | Preventing infection at mucosal surfaces 40
Techniques in Immunology 43
Chapter 11 | Immunological memory and vaccination 45
Chapter 13 | Failures of the body’s defenses 49
Chapter 14 | IgE-mediated immunity and allergy 53
Chapter 16 | Autoimmune diseases 56
Chapter 17 | The immune system and cancer 58
2
, Chapter 1 | Elements of the immune system and their roles in defense
- Why do we have an immune system?
- Our immune system ensures we stay healthy
- Immune system: a di use+complex network of interacting cells, cell products, and cell-
forming tissues that protects the body:
- From pathogens and other foreign substances (e.g. viruses/bacteria/parasites/
fungi)
- Destroys infected+malignant cells (to eliminate tumor growth)
- And removes cellular debris; wound healing
- Immunity:
- Our immune system needs to discriminate between self vs non-self AND harmless vs
harmful
- Pathogens — non-self + harmful
- Microbiome — non-self + harmless; keeps us healthy, so don’t want immune
system to ght them o
- Cancer — self + harmful; own cells that grown unnaturally and cause disease
- Tissues+organs — self + harmless
- Tissues: group of cells with similar structures, working together to perform a
shared function
- Organs: structures made up of a group of tissues, working together to
perform speci c functions
- Health — immune response towards harmful substances (either self or non-self);
no immune response towards harmless
- There is a delicate balance in immune activation (in ammation) and inhibition
(tolerance)
- The balance between tolerance and in ammation always needs to be restored
- A dysbalance in immunity can cause (severe) diseases
- Infection — non-self + harmful
- Allergy — non-self + harmless
- Cancer — self + harmful; no reaction to harmful cells -> cancer
- Auto-immune disease — self + harmless
- Disease — immune response towards harmless substances (either self or non-
self); no immune response towards harmful
- How to treat immune-related disease?
- In order to restore the balance of in ammation-tolerance; disease -> health
(immune response towards harmless -> harmful)
- Infection -> vaccines
- Cancer + auto-immune disease -> immunotherapy
- Before we can use our immune system for treatment, we need to know what the right
balance is, how it’s achieved, and what exactly causes dysbalance
- Innate vs adaptive immunity - components:
- In our blood we can nd multiple immunological components:
- Red blood cells / erythrocytes
- Platelets
- Plasma (consisting of molecules: antibodies+complement)
- Complement is proteins, not cells
- White blood cells / leukocytes (divided into di erent types of immune cells:
neutrophil, eosinophil, basophil, monocyte, lymphocyte)
- Neutrophil is most abundant, followed by lymphocyte
- -> draw blood for research
3
fi fi fi ffff fl fl ff fl
, - These cells+molecules are subdivided in 2 main immunological categories: innate vs
adaptive immunity
- Innate immunity consists of:
- Granulocytes (containing toxic granules): basophil + eosinophil + neutrophil
- Monocyte
- Complement
- Lymphocyte -> NK cells
- Adaptive immunity consists of:
- Lymphocyte -> B cells + T cells
- Antibodies
- Lymphocyte is subdivided in both innate and adaptive immunity -> NK cells
(innate) and B+T cells (adaptive)
- Hematopoiesis: the development of immune cells with 2 important common precursors
- Hematopoietic stem cell — found in bone marrow
- -> common lymphoid precursor -> lymphocytes (adaptive, except NK cells)
- B cell (-> plasma cell) + T cell (-> e ector T cell) + NK cell
- -> common myeloid precursor -> myeloid cells (innate)
- Granulocytes (incl. mast cell) + monocyte (-> macrophage + dendritic cell)
- Platelets + erythrocytes (from di erent progenitor)
- Monocytes have a di erent function due to di erent precursor
- Granulocytes have common precursor and are relatively similar, but react to
di erent things
- Macrophages, dendritic cells, and mast cells can be found in our tissues; other
cells can be found in our blood
- Dendritic cells are innate immune cells, but is very important for activation of
adaptive immune cells
- Immunity is subdivided into 3 lines of defense based on the speed of activation upon
danger:
1. Innate immunity — physical/epithelial barriers (skin, mucous membranes,
chemicals, low pH that make sure pathogens don’t get in)
2. Innate immunity — innate immune cells (phagocytosis, complement,
interferon, in ammation, fever)
3. Adaptive immunity — adaptive immune cells (lymphocytes, antibodies)
- We have innate and adaptive immunity including circulatory system (white blood cells,
antibodies, complement) and lymphatic system:
- The lymphatic system is subdivided into primary and secondary lymphoid
organs with di erent functions:
- Primary — development of adaptive immune cells: bone marrow (B cells),
thymus (T cells)
- Secondary — activation of adaptive immune cells: lymph nodes (present
everywhere in body), spleen, Gut Associated Lymphoid Tissues (GALT)
- Secondary lymphoid organs are highly structured with speci c sites for T cell
and B cell activation (T cell zone, B cell follicle, germinal center)
- Dendritic cells activate T+B cells in secondary lymphoid organs during infection
- Innate vs adaptive immunity - function:
- Your innate and adaptive immune system di er in the speed and speci city of
inducing immunity:
- Innate immunity - response against danger: immediate+fast (minutes, hours),
equal in all of us (‘existing in one from birth’), pathogen recognition receptors
- Adaptive immunity - response against danger: adapted+slow (days, weeks),
highly speci c for each type of danger (‘able to adapt’ -> di erent in all of us),
broad repertoire speci c receptors, memory (gives immunity)
- Macrophages and neutrophils are fast responders upon bacterial infection and
induce in ammation
- Macrophages present in tissue; neutrophils present in blood
- Healthy skin is not in amed
4
ff
fl fifl ff flfffi ff ff ffff fffi fi
