Topic 2: Fundamentals of the Immune System Flashcards
Innate and adaptive: physical barriers
Innate: skin, mucous, cilia, hair, flushing mechanisms
Adaptive: nil
Innate and adaptive: physiological barriers
Innate: pH, temp
Adaptive: nil
Innate and adaptive: diversity and specificity
Innate: non-specified
Adaptive: highly specific, customised responses
Innate and adaptive: typical speed on onset
Innate: quick
Adaptive: slow at first exposure, but quicker subsequent exposures
Innate and adaptive: ability to adapt
Innate: no
Adaptive: yes
Innate and adaptive: immunological memory
Innate: no
Adaptive: yes
Innate and adaptive: key immune cells involved
Innate: mast, dendritic, microphages, macrophages, natural killer
Adaptive: B-cells –> antibodies, T-cells:helper, killer. memory, suppressor
Innate and adaptive: weapons used
Innate: enzymes, acid, interferons, cytokines, complement
Adaptive: antibodies and killer T-cells
Innate and adaptive: soluble (humeral) factors/molecules
Innate: cytokines, complement, interferons
Adaptive: antibodies
What are some functions of the immune system?
maintain cellular, tissue, system and whole body homeostasis
What is homeostasis?
maintenance of optimal body/system/organ/cell function
What aspects are regulated through homeostasis at a cellular and tissue level?
Cellular: cell volume, osmolarity, electrolyte concentration, intracellular pH, membrane potential, concentrations of substances (PRRs)
Tissue: cell number and composition, tissue architecture, concentration of substances, pH, temperature, osmolarity (PRRs)
What must a pathogen do to cause disease?
- gain access to body
- attach to/enter host cells
- reproduce while avoiding the immune system
What is the primary system of the immune system and what does it do?
Lymphatic system
- housing system for immune cells
- transport
What are the organs of the immune system?
lymphatic tissues
What are the primary lymphatic tissues?
Bone marrow: produces all immune cells
Thymus: matures T-cells
What are the secondary lymphatic tissues?
Lymphatic vessels: passively drains lymph from tissue
Lymph nodes: monitor lymph for infection, house lymphocytes
Mucosa: traps potential infectants, mast cells
Spleen: house mature T- and B cells, filters RBC
What are the different cells of the immune system?
Erythroid: RBC, platelets
Myeloid: microphage (neutrophil, eosinophil, basophil), monocytes –> macrophages, mast cells, dendritic cells
Lymphoid: large lymphocytes (natural killer), small lymphocytes (B-cells, T-cells)
What does myeloid lineage include?
microphages (neutrophil, eosinophil, basophil), monocytes –> macrophages, mast cells, dendritic cells
What are macrophages?
migrate to vascularised tissue and break down cell walls with enzymes
What are mast cells?
found in areas with high amounts of blood, prominent near internal/external barriers, present in tissue trauma
What are dendritic cells?
tissue-resident, introduces pathogens to immune system
What are the cells of adaptive immunity?
T-cells, (helper, cytotoxic, suppressor), B-cells (plasma cells), dendritic cells
What are the large lymphocytes?
natural killer cells - kill pathogens
What are the small lymphocytes?
B-cells, T-cells
B-cells
B cells: produced + mature in bone marrow, plasma –> antibodies, memory
Helper-T cells
secrete cytokines, amplify antibody production
Cytotoxic T-cells
kill cells, enzymes, live in thymus
Suppressor T-cells
dampen/suppress immune response
Memory T-cells
recognise original invading antigen, immunological memory
What are the molecules of the innate and adaptive immune systems?
Innate: cytokines (chemokines, interleukins, interferons), complement
Adaptive: antibodies
Cytokines
- used for communication between immune cells
- cell activation and deactivation, up- or down- regulate synthesis
What are the types of cytokines?
Chemokines: guide immune cells to infection site, ‘chemical trail’
Interleukins: communication between leucocytes
Interferson: produced and released by host cells in response to presence of pathogens
What is the complement system?
proteins circulating within the blood stream and break down cell walls, facilitates inflammation
What are the key defence mechanisms?
Innate: first line of defense, cellular
Adaptive: second line of defense, highly specific
What are the physical barriers of the first line of defence?
skin, mucous membranes, hair, cilia
What are the mechanical barriers of the first line of defence?
vomiting, coughing, sneezing, urinating, defecating
What are the physiological barriers of the first line of defence?
pH, temperature
What are the chemical barriers of the first line of defence?
nitric oxide, catabolic enzymes, cytotoxic proteins, acid, lysosomal enzymes (saliva, ear wax, sebum, sweat glands), physical properties (ie sticky wax, mucous)
What is the innate cellular immune response?
non specific, no immunological memory, deals with pathogens the same way every time
What are the cells of innate cellular immunity?
macrophages, mast cells, natural killer, dendritic
Eosinophils
degrade pathogens with cytotoxic substances, explosive
Neutrophils
principal phagocytic cell, collateral damage, suicide by apoptosis
Basophils
similar to eosinophils and mast cells, explosive
What is the adaptive immune system?
highly specific, immunological memory
What is immunological memory?
faster and stronger subsequent responses - antibodies produced in secondary response = greater affinity for antigen
How is the immune response triggered? (pathogens)
- pathogens invade host
- pathogens release PAMPs
- PAMPs recognised by PRRs in innate system
4, PAMPs captured by innate immune cells and presented to other immune cells
What are PAMPs?
pathogen-associated molecular patterns, induce inflammation, identify pathogens to innate immune cells
What are PRRs?
pattern-recognition receptors, surface receptors on resident innate immune and parenchymal cells that response to PAMPs, trigger response of other immune cells
What are inducers of inflammation?
PAMPs, DAMPs, pH, hyperoxia, obesity/overweight, lifestyle factors
What are some examples of when immunity goes wrong?
allergies, arthritis, anaphylactic shock, cancer, septic shock, transplant rejection, HIV
How is the immune response triggered? (no pathogens)
- tissue damage
- DAMPs released by distressed/damaged/dying cells
- DAMPs recognised by PRRs in innate system
- DAMPs captured by innate cells
