Innate Immunity

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What three aspects are there to constitutive physical defences?
Mechanical, Beneficial Microbial Interactions, Constitutive Antimicrobial Defences
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How can Helicobacter Pylori survive the acidic conditions in the stomach?
By neutralising acid in transit (using urease to liberate ammonia), and then getting under mucus layer and attaching to epithelia where pH=7
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What 3 things do normal columnar epithelial cells exhibit?
1) tight junctions 2) production of antimicrobial peptides 3) apically attached and secreted MUCINS, which form glycocalyx (a fuzz-like coat on the PM).
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What are M cells? How do they differ from normal epithelial cells? What does M stand for?
Specialised epithelial cells found in gut-associated lymphoid tissue. Reduced mucin secretion and modified apical and basolateral surfaces. Microfold cells.
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What can specialised dendritic cells do?
Extend dendrites between tight junctions to sample luminal contents
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Where is bile produced?
Hepatocytes in liver
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Where does it go?
It drains through bile ducts penetrating the liver
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What is it made alkaline by?
A bicarbonate-rich watery solution secreted by epithelial cells
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What does it do?
1) neutralised stomach acid before entering ileum 2) acts as a bacerticide 3) selectively lyses streptococcus pneumonide
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Why is it bad to take antibiotics?
Decimates populations of commensal micro-flora in the COLON, providing the opportunity for pathogenic bacteria to populate the colon and cause further disease
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What does the coagulation system do?
1) seals wounds 2) physically traps invading microbes in blod clots 3) increaes vascular permeability (links to inflammation) 4) recruits leukocytes to site of injury 5) has direct antimicrobial activity
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What are cells of the immune system derived from?
Hematopoietic stem cells
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what are the three lineages of blood cells, and what do they include?
LYMPHOID: B cells, T cells and NK cells ERYTHROID: platelets and erythrocytes MYELOID: granulocytes (neutrophils, eosinophils and basophils), mast cells, monocytes and dendritic cells
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How can they be separated out?
Using flow cytometry... FACS (Fluorescence Activated Cell Sorting). Principle = antigen-antibody reaction, whereby antibodies are fluoresecently labelled
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What are macrophages found in the a) lungs b) bone c) liver d) brain referred to as?
a) alveolar macrophages b) osteoclasts c) kupffer cells d) microglia
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What are the two main classes of defensins? Give examples, and what they are secreted by.
alpha and beta. ALPHA: e.g. HD5 and HD6 (cryptidins)- secreted by panted cells. BETA: e.g. HBD1-4- secreted by epithelial cells
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What else do paneth cells secrete?
lysososyme and phospholipase
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What are the two main subfamilies of pentraxins? Given example and what they are secreted by.
short and long. SHORT: e.g. serum amyloid/P component- secreted by liver hepatocytes. LONG: e.g. PTX3- secreted by monocytes, macrophages, DC's and epi/endothelial cells
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What is a NET?
Neutrophil Extracellular Trap- formed by release granule proteins and chromatin by neutrophils to form an extracellular fibril matrix
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What do they do?
provide high local concentration of antimicrobial proteins and a physical barrier preventing further spread ph pathogens.
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Give an example of the mechanisms that microorganiss have evolves to escape NETs
Secretion of DNAse
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What do C-type lectin receptors recognise?
Carbohydrates
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Name the two cytosolic cytokine receptors
Nod-Like Receptors and RIG-like receptors
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What do a) NOD1 receptors b) NOD2 receptors recognise?
a) gamma-glutamyl diaminopimelic acid (a product of peptidoglycan of game -ve bacteria) b) muramyl dipeptide (degradation product derived from peptidoglycan in most bacteria)
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What is it called when a cytokine acts on a) the cell that secretes them b) nearby cells c) distant cells
a) autocrine b) paracrine c) endocrine
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How do cytokines exert their effects?
By binding membrane receptors and then signalling via second messangers to alter gene expression
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Name the cytokines that a) are made by lymphocytes b) are made by monocytes c) have chemotactic activities d) are made by one leukocyte, and act on another
a) lymphokine b) monokine c) chemokine d) interleukin
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What can cytokines effects depend on?
The location of tissue
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Cytokines effect in a) bone marrow b) Liver c) dendritic cells
a) neutrophil mobilisation ==> phagocytosis b) acute-phase proteins ==> complement + opsonisation c) TNF-alpha stimulates migration to lymph nodes ==> adaptive immune response initiation
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d) hypothalamus e) fat/muscle
BOTH: increased body temperature ==>decreased viral and bacterial replication, increased antigen processing and adaptive immune response facilitation
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What does S-LeX stand for? What is it?
Sialyl-Lewis X. A tetrasaccharide on leukocyte surfaces that bind to selectin
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What is it called when neutrophils squeeze between epithelial cells and penetrate connective tissue?
Diapedesis
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Which cells exist in a) the tissues b) the lymph nodes
a) macrophages, mast cells and immature dendritic cells b) NK cells, B cells, T cell and mature dendritic cells
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Other cards in this set

Card 2

Front

How can Helicobacter Pylori survive the acidic conditions in the stomach?

Back

By neutralising acid in transit (using urease to liberate ammonia), and then getting under mucus layer and attaching to epithelia where pH=7

Card 3

Front

What 3 things do normal columnar epithelial cells exhibit?

Back

Preview of the front of card 3

Card 4

Front

What are M cells? How do they differ from normal epithelial cells? What does M stand for?

Back

Preview of the front of card 4

Card 5

Front

What can specialised dendritic cells do?

Back

Preview of the front of card 5
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