BIOL1008 Lecture Notes - Lecture 20: Innate Immune System, Microorganism, Immunology
9 Jun 2018
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Lecture 20: Innate immunity and inflammation
What is the immune system?
- A collection of cells, tissues, and molecules that mediate resistance to infections and
eliminates tumours
- Immunology is the study of the immune system and its responses to invading pathogens
and tumours
- The coordinated and tightly controlled reaction of the Immune System to infectious
microbes is alled The Iue Respose
- The function of the immune system is:
to prevent infections
to eradicate established infections
to detect and eliminate tumours as well as tolerate self
What is immunity?
- Immunity is often defined as resistance to disease
- Specifically, infection diseases caused by:
Bacterial infections
Viral infections
Fungal infections
Parasitic infections
- In recent years, this has been extended to include tumour immunity
- Immunity is not just about killing microbes- it is part of a broader set of functions that
are more about keeping our bodies in good working order
The power of the immune system
We can learn so much about the importance of the immune system by observing those who
have a defective immune response:
- Congenital (primary) immune deficiencies
E.g. patients who completely lack key cells and molecules of the immune system
- Acquired (secondary) immune deficiencies
E.g. HIV infection that leads to the eradication of key immune cells
We also gain an appreciation and respect for the immune system when it over-reacts:
- Asthma
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2
- Atopic or allergic reactions
- Causing autoimmune diseases (e.g. multiple sclerosis, SLE, insulin-dependent diabetes
mellitus)
The impact of immunology goes beyond infectious diseases:
- Transplantation (immunity is the reason for graft rejection)
- Tumors (immunity can be the cure and the cause)
David Vetta: bubble boy
- 1971- 1984
- Had a congenital immunodeficiency called SCID
- Lived almost his entire life in a specially- constructed bubble-shaped sterile environment
- Treatment plan was to give him a bone marrow transplant from his older sister
- Died fro Burkitt’s lphoa at the age of
- Had to rely almost entirely on innate immunity
Where is the immune system?
The immune system is integrated with other systems:
- Gastrointestinal, cardiovascular, respiratory, nervous, endocrine, skin
Immune cells are scattered in call parts of the body:
- Many of them actively travel or migrate around it
- Others sit in the one place for a long period of time
Often referred to as resident cells
Molecules of the immune system can act in an:
- Autocrine e.g. yelling loud to hurt own ears
- Paracrine e.g. yelling loud and hurting others near by
- Endocrine manner (when secreted) e.g. yelling loud and hurting others ears on other
side of campus
These are just analogies
The anatomy of the immune system
- Physical & chemical barriers
Epithelial cells of skin, gut, respiratory tract
Secretions including sweat, wax and tears
Mucus in the nose, trachea, gut
Urine
Proteolytic enzymes
Low stomach pH
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Document Summary
A collection of cells, tissues, and molecules that mediate resistance to infections and eliminates tumours. Immunology is the study of the immune system and its responses to invading pathogens and tumours. The coordinated and tightly controlled reaction of the immune system to infectious microbes is (cid:272)alled (cid:862)the i(cid:373)(cid:373)u(cid:374)e respo(cid:374)se(cid:863) The function of the immune system is: To detect and eliminate tumours as well as tolerate self. Immunity is often defined as resistance to disease. In recent years, this has been extended to include tumour immunity. Immunity is not just about killing microbes- it is part of a broader set of functions that are more about keeping our bodies in good working order. We can learn so much about the importance of the immune system by observing those who have a defective immune response: E. g. patients who completely lack key cells and molecules of the immune system. Hiv infection that leads to the eradication of key immune cells.
