Immunology Flashcards
Immune System
Collection of cells, tissue, and molecules that mediate resistance to foreign elements (antigens)
Immune Response
Coordinated reaction of these cells and molecules to antigens
Immunology
Study of the immune system, including its responses to microbial pathogens and damaged tissues and its role in disease
Antigen
Antibody generator (generate an immune response)
Molecule that induce an immune response when introduced into the body
Epitope or antigenic determinant
Part of an antigen that is actually responsible for inducing the immune response and binding to the products of the immune response (lymphocyte receptors and antibodies)
When should immune responses be generated
when components of the immune system come into contact with non-self elements
What is the result of autoimmunity?
if the system does not discriminate foreign elements from components of its own organism
What are the two type of immune system defence?
Innate Immunity
Adaptive Immunity
What are the key features of innate immunity?
Physical barriers
Inflammation
Complement
What are the adaptive immunity key features?
Humoral Immunity
Cellular Immunity
What is the activation status of innate immunity
Always active
What is the activation status of Adaptive immunity?
Only when in contact with antigens
What are the main cells of innate immunity?
Macrophages, Neutrophils, NK cells
What is the response time for Innate immunity
Fast (minutes to hours)
What is the main cells of Adaptive immunity
T cells and B cells
What is the response time for adaptive immunity?
Slow (days to week)
what is innate immunity specificity
structure common to several pathogen
What is the memory of innate immunity?
Absent
What is the adaptive immunity specificity
Specific to epitope, typically unique to a pathogen
What is the memory of adaptive immunity?
Present
Pathogen-Associated Molecular Patterns
Components that are shared between different types pathogens and present a molecular composition that differs from “self”
- pathogen is the trigger
Damage-Associated Molecular Patterns or DAMPs
Released when cells die* (intracellular DAMPs) or generated when connective tissue is damaged (extracellular DAMPs)
- damage is the trigger
What are PRP (Pattern Recognition Receptors)
Receptors of innate immunity that recognize PAMPs & DAMPs
Soluble or membrane-bound
Signalling or phagocytic
What is this?
Neutrophil
Describe the Neutrophils
Appearance: Segmented nucleus, granular cytoplasm
Location in health: Blood
Life span in health: 48-72 hours (relatively short life)
Primary function: Antimicrobial effectors, particularly in acute bacterial infection
Mechanism of action: Phagocytosis; Degranulation; Neutrophil extracellular trap formation
What is this?
Eosinophils
Describe Eosinophils
Appearance: Characteristic eosinophilic granules
Location in health: Blood and tissues lining gastrointestinal tract and airways
Life span in health: Days to weeks
Primary function: Antiparasitic effectors, particularly in helminthic infection; Some antiviral action; Roles in allergy
Mechanism of action: Degranulation; Limited phagocytosis
Describe Basophil
Appearance: Characteristic blue-purple basophilic granules
Location in health: Blood
Life span in health: Days
Primary function: Mediator of inflammation
Mechanism of action: Degranulation
What is this?
Basophil
Describe Mast cells
Appearance: Round nucleus, cytoplasm densely packed with purple granules
Location in health: Tissue, particularly connective tissue surrounding vasculature and nerves, and the lamina propria of the mucosa
Life span in health: Weeks to months
Primary function: Immune surveillance, mediator and amplifier of inflammation and allergy
Mechanism of action: Detection of threats and release of response inflammatory mediators via degranulation (vasoactive amines)
or synthesis of lipid mediators and cytokines
What are the innate cells of the immune system
Neutrophils
Basophils
Eosinophils
Mast cells
What are phagocytes?
Macrophages
Dendritic cells
What is the most important cell in the adaptive immune system
Dendritic cells
Describe Dendritic cells
Appearance: Round nucleus, clear cytoplasm, irregular shape with long branched projections (dendrites)
Location in health: Tissues
Life span in health: Months
Primary function: Immune surveillance, antigen processing and presentation
Mechanism of action: Detection of threats and release of inflammatory mediators; Endocytosis and phagocytosis
What type of cell is this
Mast cell
Describe Macrophages
Appearance: Round nucleus, clear-vacuolated cytoplasm, irregular cell shape
action small in
Location in health: Peripheral tissue
Life span in health: Months
Primary function: Immune surveillance, moderate antimicrobial capacity, limited antigen presentation
Mechanism of action: Detection of threats and release system of inflammatory mediators; Phagocytosis
What are lymphocytes
NK Cells (Natural Killer)
Lymphocytes
Describe Na Killer?
Appearance: Large lymphoid cell, round nucleus, azurophilic cytoplasmic granules
Location in health: Blood, spleen
Life span in health: Months
Primary function: Destruction of virally infected or abnormal host cells (including tumor cells)
Mechanism of action: Recognition of virally infected or abnormal host cells and targeted release of cytotoxic granules
What type of cell is this?
Macrophages
What type of cell is this?
Dendritic cell
What type of cell is this
NK cell (Natural Killer)
What type of cell is this?
Appearance: Round nucleus, clear cytoplasm, high N:C ratio
Location in health: Blood, tissues, secondary lymphoid organs
Life span in health: Weeks to months, years (Memory cells)
Describe Lymphocyte
Appearance: Round nucleus, clear cytoplasm, high N:C ratio
Location in health: Blood, tissues, secondary lymphoid organs
Life span in health: Weeks to months, years (Memory cells)
What are the two major types of lympthocytes
T cells and B cells
Complement system
Collection of plasma proteins that are individually inert but can interact in a cascade once they are activated
Attacks the cellular membrane leading to cell death
Act as signalling molecules that recruit immune cells to inflammatory sites
How does the immune system communicate ?
Cell-to-cell contact - using receptors and ligands
Cytokines
What are receptors and ligands
Receptors
* Expressed on the surface of a cell or in intracellular compartments
Ligands
* Molecules that activate receptors
* Soluble or membrane-bound
What are Cytokines
Proteins with diverse functions such as cell growth, activation
Interleukins
- Communication between cells
Chemokines
- Chemotaxis
