How to React to Danger
Page 1: Overview of Immunology
Context: Summary of immunology in four lectures
Lectures 1-2: General design of the immune system
Lectures 3-4: Diseases of immune excess and immune deficiency
Page 2: Immune Response
Four key points:
How immune responses start
Development of immune responses
Immune-mediated diseases and therapies
Enhancing the immune response through vaccination
Page 3: Understanding Danger
Concept of danger:
Damage recognized by the immune system
Page 4: Reacting to Danger
Recognizing danger molecules
The anatomy of the immune response:
Highlighting key immune components
Innate immune cells as the body’s heroes:
Role of innate immune cells in response
Page 5: Immunological Danger
Key pathogens and diseases:
SARS-CoV-2 (COVID-19)
Plasmodium falciparum (malaria)
Salmonella typhimurium (infection)
Page 6: Under Attack!
External Epithelia
wounds
insect bites
Skin surface interactions
Mucosal Surface
Airway
Gastrointestinal Tract
Reproductive Tract
Page 7: Defenses
Main defense mechanisms:
Mucus secretion
Ciliary action
Production of defensins (antimicrobial peptides)
Page 8: The Response - Inflammation
Introduction to inflammation:
Role of Pattern Recognition Receptors (PRRs) on immune cells
Importance of toll-like receptors (TLRs) in immune recognition
If something goes wrong - barrier breach, pattern recognition receptors recognise patterns of potential danger. This is called inflammation
Page 9: Initiation of Inflammation
Key triggers of inflammation:
Various molecules from pathogens (e.g., lipoproteins, lipid A, flagellin)
Recognition through TLRs (e.g., TLR2, TLR4, TLR6)
Additional receptors like NOD1 and NOD2
Page 10: The Start of Inflammation
Key inflammatory mediators:
Histamines, peptides, cytokines, chemokines
Page 11: Inflammation Symptoms
Clinical signs of inflammation:
Scab formation, rubor (redness), calor (heat), tumor (swelling), dolor (pain)
Loss of function associated with inflammatory response
Page 13: The Lymphatic System Map
Overview of the lymphatic system - like the subway
Lymphatic vessels as connecting pathways
the lines that connect the system
Lymph nodes is a point in a network at which lines or pathways intersect or branch
the stations
Lymph is a colourless fluid containing white blood cells that drains through the lymphatic system into the bloodstream
the train carriages
Page 14: Key Lymphatic Components
Notable lymphatic locations:
thymus, spleen, lymph nodes
lymph nodes immune system also has more specialised lymphoid organs
thymus is where T cells are made
spleen responsible for filtering blood.
Page 15: Lymph nodes
Anatomical details:
Various veins and lymph glands involved in lymphatic drainage
the lymphatic system is similar to the blood vessel system. Lymph nodes, are often found where blood vessels meet or join together.
Page 16: Lymphatic Anatomy
blood enters through arteries and exits through veins
Lymph coming in through lymphatic vessels and leaves through lymphatic vessels.
Lymph nodes are points for meeting of cells, they connect everything.
Page 17: Next Steps: Molecules and Anatomy
Focus areas for understanding the immune response:
Molecules involved (PRRs) - inflammation
Lymphatic anatomy and its role in immunity
Page 18: Blood Cells Overview
Importance of blood cells:
Function of red blood cells (oxygen transport)
Function of white blood cells (immune cells)
Page 19: Red Blood Cells Facts
Key facts about red blood cells:
Normal count: 5-6 million cells/µl
Lifespan: ~110 days
Role in transporting O2 and CO2
Page 20: White Blood Cells
Types of white blood cells:
Innate immune cells
neutrophils, macrophages, dendritic cells
basophils, eosinophils, mast cells, monocytes
Adaptive immune cells
B cells, T cells,
Page 21: Innate vs Adaptive Immunity
Comparison of immune responses:
Innate immunity: Immediate response, non-specific
epithelial barriers
phagocytes
dendritic cells
complement
NK cells
Adaptive immunity: Delayed response, specific, involving B and T lymphocytes
innate immunity for first 12 hours, adaptive for 1-5 days
Page 22: Complement System
Overview of complement system:
Initial complement protein activation through antibodies
Importance of complement cascade in immune function
antigen binds to antibody - first compliment protein is activated, leading to a series of further complement proteins - compliment cascade
Complement is not a cell. It is a cascade of protein that senses danger
Page 23: Function of Complement
Key roles of complement:
amplifying inflammatory response
directly killing pathogens and recruiting immune cells
Page 24: Key Cells in Blood
Important blood immune cells:
Neutrophils, macrophages, and dendritic cells
Page 25: Neutrophils - Key Facts
Characteristics of neutrophils:
Most abundant white blood cells
Phagocytic activity against pathogens
consume and kill pathogens, using NETs
Recruitment to sites of inflammation
act fast and die fast
Page 26: Macrophages - Key Facts
Characteristics of macrophages:
Develop from tissue precursors
also consume and kill pathogens
Active phagocytic cells with long lifespan
always there - activated by inflammation
Tattoo - barrier breach and activates the macrophages and eats the ink and holds it. If macrophage dies, another one eats the ink.
Page 27: Dendritic Cells - Key Facts
Characteristics of dendritic cells:
Development in tissues from precursors
active phagocytic cells
Migrate out of peripheral tissues
Carry proteins to lymph nodes to Activate adaptive immune responses
unlike other, main job is not to eliminate but to pick up danger molecules and migrate to lymph codes where it meets T-cells and B-cells
Page 28: Reacting to Danger
Key components in responding to danger:
Recognizing danger via pattern recognition receptors (PRRs)
Mapping of immune response through lymph nodes and innate immune cells (neutrophils, macrophages, dendritic cells)