Immunology Flashcards
Variology
exposure of an individual to the contents of dried smallpox pustules from an infected patient
major job of immune system
to identify and eliminate microorganisms and other harmful substances as well as abnormal cancer cells
Under deficient immune system leads to
recurrent infections and cancer
Over efficient immune system may cause
allergies or auto immune diseases
How does the immune system identify and eliminate microorganisms
By distinguishing ‘self’ molecules from ‘non-self’ molecules or by identifying ‘danger’ signals
Example of danger signal
acute Inflammation
Physiological Immune Deficiency
Extremes of life: ageing or prematurity
Infections causing secondary immune deficiency
HIV, measles
Treatment interventions causing a secondary immune deficiency
immunosuppressive drugs, anti-cancer agents, corticosteroids
Biochemical and nutritional disorders causing a secondary immune deficiency
Malnutrition, renal dialysis/ insufficiency, diabetes
Malignancy causing a secondary immune deficiency
cancer of immune system
examples of how the immune system may be manipulated
immunisation, antiinflammatory and immunosuppressant drugs, cancer immunotherapy
Physical barriers to infection in innate immune system
skin, mucous, commensal bacteria
Why is skin a good physical barrier?
physically (tightly packed cells), physiologically (low pH 5.5) and sebaceous glands (secretes hydrophobic oils, lysosomes and defensins)
What do Commensal Bacteria do?
anti microbial short chain fatty acids which kill pathogens, compete for essential nutrients, reduce pH go the bowel, synthesis of vitamin K, B12
Why is mucous a good barrier?
it’s found in respect, urogenital, gastrointestinal and secret IgA, enzymes such as defensins, antimicrobial peptides which directly kill pathogens and also the Celia cells remove pathogens trapped in mucous through a cough or sneeze
How fast is the innate response
rapid (0-96hours)
How long has the innate response been present
since birth
How does the innate response affect immunological memory
there’s no immunological memory
Is the innate response specific or non-specific
non-specific
How does the innate response distinguish what cells are ‘dangerous’
it can recognise self and non-self antigens and will only react against non-self
what cells are involved in the innate response?
Mast cells, NK cells, Phagocytes (macrophages, neutrophils and dendritic cells) and complement
What do innate cells express?
Pattern recognition receptors (PRRs)
What do pathogens express?
Pathogen associated molecular patterns (PAMPs)
opsonisation
coating of pathogens by soluble factors (opsonins) to enhance phagocytosis
examples of opsonins
C3b, IgG/IgM, C-reactive protein (CRP)
What happens ig pathogens are to big to be engulfed
Mast cells step in
What do mast cells do
The PRRs on the Mast recognise the PAMPs on the pathogen causing it to degranulate, releasing histamine and cytokines
What role do macrophages play in the innate immune response?
The macrophages express PRRs on the surface of the cell which recognise the PAMPs on the surface of the pathogens, when bound this triggers macrophages to undergo phagocytosis, creating MHC class II, releasing debris and releasing pro inflammatory mediators (TNF-alpha)
What are primary lymphoid tissues
anatomical sites where the white blood cells (leukocytes) are produces
examples of primary lymphoid tissues
bone marrow- B cells
thymus- T cells
examples of secondary lymphoid tissues
spleen and lymph nodes
How long does it take to trigger the innate immune response after infection
minutes
How long does the innate immune response last
days
