Immune Flashcards
What are the three main benefits of the body as a habitat for potential pathogens?
Nutrient source
Good setting for growth and reproduction
A good vector for transmission
Name some potentially harmful organisms.
Viruses Bacteria Fungi Protozoa Helminths
What are the physical barriers of the body?
Skin - sheds old cells and bacteria
Dendritic (langerhan’s) cells present antigens
What are the main chemical defences of the body?
Anti microbial peptides Lysozyme Sebum Salt Tears contain lysosomes
Where are anti microbial peptides found, and what is their role?
In sweat, they interrupt cell growth.
Where are lysosomes found and what is their role?
Found in sweat and tears, breaks down cell walls.
What is the role of salt on the skin?
Creates an osmotic gradient for bacteria, drawing water out of the cell.
Where are mucosal membranes found?
Ocular, respiratory, oral and urogenital tracts
Briefly describe the muco-ciliary escalator
Goblet cells produce mucous, which traps microbes and duct, cilia beat in time and move mucous up the throat where it can then be swallowed or removed.
What is the role of micro flora?
They are better adapted to our bodies than bacteria and so they out compete them. Help us develop immunity and produce anti microbial peptides. They can cause opportunistic infections.
What are the features of the GI tract which protect against infection?
Low pH, toxic bile from gall bladder, digestive enzymes, mucus
What features of the urogenital tract helps prevent infection?
The osmotic gradient
Urine flow
Low pH
What do TLR’s distinguish between?
Self, harmless non self and harmful non self
How do TLR’s work, where are they found and give an example?
They recognise structures unique to microbes, are found on membranes of our immune system cells and an example is TLR - 5 which recognises flagellin.
What effects does TLR activation have?
Activation of the immune system, release of anti microbial peptides, and inflammation.
What is found in blood plasma?
Compliment proteins and antibodies.
Where are WBC’s produced?
In the bone marrow
What is the name for any blood cell which is not a lymphocyte?
Myeloid cells
What are the four types of granulocytes?
Neutrophils
Eosinophils
Basophils
Mast cells
What is the function of neutrophils?
Highly phagocytic
Most abundant leukocyte at 40 - 75%
Have a half life of 1-2 days
What is the function of eosinophils?
1-6% of WBS’s
Phagocytic and releases toxic granules
Mediates allergic reactions
What is the function of basophils?
Low number in blood 0.5% total WBC’s
No phagocytosis
Mediates allergic reactions and fights worm infection via granule release
What is the function of mast cells?
Line mucosal surfaces
Release granules which attract white blood cells
Describe the monocyte to macrophage transformation.
Monocytes have low phagocytic abilities. They then develop into macrophages which have high phagocytic abilities. They can either become sessile or migratory.
Describe dendritic cells.
Present in blood and all tissues in contact with the environment. They are phagocytic and good APC’s, triggering the acquired immune response.
What is the purpose of lymphatic vessels?
They drain ECF and lymph tissues, providing a site for immune system and antigen interaction.
What is the role of the spleen?
Filters blood antigens.
Where are different cells found in the lymph node?
APC’s present antigen to T(h) cells in the cortex
T cells influence B cells in the medulla.
What are the symptoms of inflammation?
Redness Swelling Loss of function Pain Heat
What occurs during inflammation?
Anti microbial peptides which interfere with microbial growth and reproduction.
Interferon is released from virally infected cells.
What do mast cells release when damaged or activated?
Histamine - Vasodilation
Prostaglandins - Vascular permeability
Leukotrines - “” “”
What functions does interferon have?
Infected cells undergo apoptosis
Uninfected cells destroy RNA and stop protein synthesis
Immune cells are activated
What are the side effects of interferon?
Muscle aches, chills, headache, fever
What are the three compliment pathways? Which one is fastest?
Classical fastest (antibody/antigen binds compliment)
Alternative (compliment binds to pathogen)
Lectin (Carbohydrate complexes of microbes bind to compliment)
What are the three main functions of complement?
Label/opsonisation coats microbe with antibody/C3b, making microbes more likely to be phagocytosed C3b
Recruitment attracts phagocytes to the area. Mast cells are degranulated. C3a and C5a
Destoy microbes, either via phagocytosis of C3b microbes or MAC complex assembly.
Breifly describe the inflammatory response
Cytokines released by mast cells and macrophages.
Fluid and leukocytes flow into the area
Phagocytosis occurs
Briefly describe a fever response.
Phagocytes release pyrogens (IL1)
This increases prostaglandin production in the hypothalamus.
This resets the set point for temperature to a higher value, hence fever
What compliment is opsonisation?
C3b