Innate Immunity Flashcards
What is the immune system?
A complex network of cells/soluble molecules which interact with one/other to remove foreign material from the body
What two types of pathogens does the immune system destroy?
- Intracellular
- Extracellular
What are the intracellular pathogens destroyed by the immune system? (2)
- Viruses (reproduce in cell)
- Some bacteria
What are the extracellular organisms destroyed by the immune system? (4)
- Bacteria
- Parasite
- Worms
- Cancer cells
What types of conditions result from errors in the immune system? (4)
- Allergic reaction
- Immunopathology
- Immune deficiency
- Autoimmunity
What is an allergic reaction? (2)
- Hypersensitivity to foreign non pathogenic antigens
- Mounting immune response to enviornmental material
What is immunopathology?
Excessive immune response causing tissue/organ damage
What is autoimmunity?
Self reactivity to own tissues/cells
What is immune deficiency caused by? (3)
- Passive maternal antibody transfer shortly before birth protects neonate
- Neonate normally develops own immune system shortly after birth
- If not: common resp problems due to loss of maternal antibodies and lack of own immunity
What are the requirements of the immune system? (2)
- Function in context of physiological functions of tissues
- Function despite evolutionary pressures
What are the two pressure on the immune system that come into conflict? (2)
- Protective
- Preservative
What is the protective function of the immune system?
The most effective means of destroying harmful pathogens
What is the preservative function of the immune system?
Immune mediated protection without disrupting normal physiological function
What is the relationship between the protective and preservative functions of the immune system?
Inverse - more protective, less preservative
What does the immune system response depend on?
The area of the body
What is a common bacteria found on the skin?
Staphylococcus aureus
What can be caused by staphylococcus aureus breaching the skin? (2)
- Cellulitis
- Tissue damage
Give 3 examples of viruses that cause infections
- Variola (small pox)
- Influenza virus
- HIV
How does HIV operate? (2)
- Attacks own body’s immune system
- Binds to T cells and destroys them
What common parasite does the immune system protect against?
Brugia malayi
What common condition does brugia malayi lead to?
Elephantitus
What is elephantitus?
Enlargement of limbs due to tissue swelling because of lymphatic blockage
Give an example of a prominent autoimmune disease
Multiple sclerosis
What causes autoimmunity?
Failure to distinguish self from non self
What is associated with tertiary stage syphilis?
Granulomatous skin “gumma”
Give a prominent example of immunopathology
Syphilis
What common system is a result of immunopathology?
Fibrosis
Give a prominent example of allergy
Rhus dermatitis
What is rhus dermatitis?
Contact allergy to poison ivy
Give a prominent example of immundeficiency
Oral candida albicans
What is oral candida albicans?
Oral thrush - yeast infection of oral cavity
What is the relationship between inflammation and innate immunity? (2)
- The inflammatory process mobilises the determinants of the innate immune response
- Turns a “random event” into an “ordered event”
How does the immune response control the inflammatory response?
Inflammation continues until switch off circuits from immune response
What is the 1st line of defence of the immune system?
Innate immune response
What does the innate immune response do at best?
Eradicates infection
What does the innate immune response do at worst?
Slows down/delays infection until adaptive immune response generated
What are the 3 parts of the innate immune system?
- Barriers
- Cellular components (cells)
- Humoral components (soluble factors)
How do the cellular components contribute to the innate immune system?
- Cell surface molecule interactions control/destroy potential threat
- Receptors on cells interact with ligands in environment causing active responses (e.g engulfment)
What do the cellular component cell surface molecule interactions in the innate immune system result in? (2)
Controlling/destroying potential threat
What type of factors are humoral components?
Soluble
What is immune cell development known as?
Hematopoiesis
What is the first pluripotent progenitor cell of the immune system?
Hematopoetic stem cell
Where are hematopoetic stem cells found?
Bone marrow
What do hematopoetic stem cells split into?
3 sets of progenitor:
- Lymphoid
- Myleoid
- Erythroid
What do lymphoid progenitor cells generate?` Give 3 examples
Lymphocytes for adaptive immune response
- B cell
- T cell
- NK cell
What do myeloid progenitor cells generate?`
- Polymorphonuclear cells (neutrophil, basophil, eosinophil)
- Mast cell
- Dendritic cell
What are the properties of a polymorphonuclear cell? (2)
- Nucleus with several lobes
- Cytoplasm with granules
What do dendritic cells do?
Deliver antigens to the adaptive immune response
What are mast cells?
Big inflammatory mediators
What do mast cells contain? (3)
- Rostoglandins
- Histamines
- Inflammatory mediators
What do mast cells do when activated?
- Deposit granules present to give rise to an inflammatory response
- Presence keeps driving information
What are macrophages?
Scavenger cells
What two cells do erythroids split into?
- Megakaryocyte
- RBC
What do megakaryocytes form?
Platelets
What is the myeloid progenitor cell responsible for overall?
Innate immune response
What is the lymphoid progenitor cell responsible for overall?
Adaptive immune response
List the cells of the innate immune system (7)
- Neutrophils
- Eosinophils
- Basophils
- Mast cells
- Natural killer cells
- Macrophages
- Dendritic cells
What is the progenitor of the cells of the innate immune system?
Myeloid
What is the purpose of neutrophils?
To kill rapidly dividing bacteria
What is the purpose of eosinophils?
Kill parasites (worms and flukes)
