ImmunologyIntroductory course
2010
Series of lectures outlining - components of immune system,
relevance to human disease
Immunology - an introduction
Conleth Feighery MD
John Jackson PhD
Derek Doherty PhD
Jacinta Kelly PhD*
Department of Immunology, Trinity College and St. James’s Hospital
* Our Lady’s Hospital for Sick Children, Crumlin
Immunology - purpose of course ?
• Learn some basic biology
• Learn about medical practice
• Learn to learn !
Immunology
What is it all about ?
• How the ‘immune system’ works
What does the immune system do ?
• 2 major functions -
• protects against infection
• causes ‘inflammation’
Major causes of ill-health
• Infection - 13 million die each year
• Inflammatory diseases - asthma
• Blood vessel disease - ‘atherosclerosis’ - heart attacks, strokes
• Cancer
Immune system plays a significant role in all these disorders.
Medical case history. 1
• 24 year old male
• Coughing and wheezing at night
• Examination - nasal speech, breathless; wheezing
• DIAGNOSIS ?
Medical case history. 1
• DIAGNOSIS - asthma
• Mechanism - “inflammation” in lungs, sinuses
• Cause - IgE, mast cells, white cells
Medical case history. 2
• 3 year old boy
• Serious lung infections x 5
• Chest X-ray - “pneumonia”
• Small size, weight
• DIAGNOSIS ?
Medical case history. 2
• DIAGNOSIS - immune deficiency
• Mechanism - unable to produce antibodies
• Antibodies “fight” infection
Medical case history. 3
• 7 year old girl
• Widespread red rash, high temperature
• Headache
• DIAGNOSIS - measles
• Cousin in same class, school - remains well
• EXPLANATION ?
Medical case history. 3
EXPLANATION -
• Cousin was given measles vaccine!
• How do vaccines work?
• Antibodies to vaccine develop - e.g. to measles vaccine
• “Educate” the immune system
• Real infection is rapidly eliminated
Immunology - terminology
• Difficult !
• “immunobabble”
• Learn some of the “language” - key terms
• Abbreviations - useful, standard
• Keep a list ?
• Use it !
Immunology - reading
• Self-learning is an objective of the University experience!
• Develop habit of seeking information - not relying on ‘being taught’
• Internet offers endless opportunities for information
Textbooks
A large variety exists - many too complex
• Few include full spectrum of this course
• B. Alberts - Molecular Biology of the Cell
• C.Janeway - Immunobiology
• H.Chapel, M.Haeney - Clinical Immunology
Immune system - components
Essential ‘nuts, bolts’
• white cells
• proteins
• organs
• circulatory system
• comprise - integral part biology
Immune system - components
• white cells - found in the blood, and tissues
• proteins - also found in blood, and tissues
• organs - such as the spleen, tonsils
• circulatory system – blood, lymphatics
Blood circulation
Cells of blood include:
• red cells - 5000 x 103 per ml - carry oxygen
• platelets - 300 x103 per ml - help clotting
• white cells - 8 x 103 per ml - immune system
Fate of circulating blood cells
• Red cells - live 120 days; in blood vessels
• Platelets - live 10 days; in blood vessels
• Neutrophils - live ~ 1 day, migrate into
tissues
• Lymphocytes - majority short lived
- some live for years
- constantly circulate
Antigen
Definition
Any substance which -
• causes a lymphocyte reaction
• reaction is specific to that lymphocyte
• clone - single type of lymphocyte which reacts to an individual antigen
Antigen
Examples -
• infectious agent - bacteria, virus
• tissue - from another person - transplant
• food !!
Lymphocytes
• Importance discovered in 1950s
• 2 x 1012 in body = size of liver
• able to transfer “immune responses” to irradiated animals
T lymphocytes
• Originate in bone marrow
• Mature in thymus
• Enter circulation
FUNCTION
• Control the immune system
• Eliminate infection - e.g. virus, fungus
B lymphocytes
• Originate in bone marrow
• Mature in bursa (equivalent)
• Enter circulation
FUNCTION
• Become antibody producing “plasma” cells
• Absence - no antibody
T and B cells - electron microscope
Alberts et al.
Resting lymphocyte ActivatedB cell
Activated T cell
Monocytes
• Originate in bone marrow
• Enter circulation
• Migrate into tissues - change shape ----
“macrophage”
• Phagocytic cell
• Present antigen to T cells
Immune system
Non-specific• Neutrophils • Macrophages• Complement• Mechanical
• “INNATE”
Specific
• Lymphocytes
• “ADAPTIVE”