Innate and adaptive immunity Flashcards
(35 cards)
Compare and contrast adaptive and innate immunity (speed, memory, specificity)
Innate = immediate, no memory, not specific Adaptive = slow, memory, specific
Innate, natural or non-specific immunity is the first line of defence. Give examples of mechanical innate immunity?
Body surfaces = skin and fur
Cilia in respiratory tract
Flushing liquids (tears, urine)
Mucus as a barrier
Give examples of physiologically innate immunity
pH changes and extremes
Pyrexia kills some infectious agents
Give examples of the 4 cellular innate defences
Macrophages
Polymorphs
Mast cells
NK cells
What do macrophages do? Which other cells are phagocytic?
Ingest/phagocytose microorganisms
Polymorphs
What do mast cells do?
Have receptors for IgE antibodies
Increase vascular permeability
What do NK cells do?
Kill tumour cells, virally infected cells or antibody coated cells
What are examples of molecular innate defences?
Defensins Complement Acute phase proteins Interferons Lysozymes Myeloperoxidase system
What are defensins? Where are they particularly found?
Small proteins
Phagocytes and epithelial
What pathogens are defensins active against?
Bacteria, fungi, viruses
Bind to microbe membrane
Important in skin barrier to infections
What are lysozyme?
Family of enzymes that attack peptidoglycan cell walls of bacteria
Where are lysozymes found?
Cells - e.g. macropahges
Secreted in tears, saliva and mucus
Sebum from sebaceous glands
Where is sebum secreted from? What does sebum do?
Sebaceous glands
Waxy fatty acids hydrate and lubricate skin
Stop bacterial attachment
What is myeloperoxidase? Which cells is it found in?
Enzyme found in lysosomes (organelle containing lysozyme and others)
Granulocytes and macrophages
What does myeloperoxidase do?
Kill bacteria and pathogens by producing toxic substances
What is the complement system?
Series of proteins that protect against microorganisms
What does the complement system do?
Opsonization
Lysis of bacteria
Recruitment of other cells to infection site
What are interferons?
Cytokines that fight viral infections and tumours
Interferons are produced early on in viral infections. Where are IFN alpha, beta and gamma produced?
Alpha and beta IFN = produced by virally infected cells
Gamma = produced by activated lymphocytes
What are acute phase proteins? How might they work?
Proteins that levels fluctuate in response to tissue injury
May bind to organism and aid removal of phagocyte
Are acute phase protein specific or non-specific? Give some examples
Non-specific
C3, C4, fibrinogen, ferritin
What is opsonisation? Why is this useful?
Coating of an infectious agent with host protein
Makes more likely to attach to phagocytes and be removed
Commensal bacteria are part of the innate immune system. Where are they found? What do they do?
Mucosal surfaces - GI, respiratory tract and skin Prevent attachment (and invasion/infection) of pathogenic bacteria
What is an adverse effect of antibiotics?
Kill commensal bacteria
Allow pathogenic bacteria to cause injury/infection
