Flashcards in Immunology Deck (37)
What is immunological unresponsiveness called to an antigen?
Define self tolerance
When immune cells and other body cells coexist peaceably
What are the physical barriers in a body?
Skin and mucous membranes in the respiratory system, digestive tract and the reproductive tracts
What is mucus made up of?
What is the function of the mucus?
Stops attachment of invading pathogens
Contains antimicrobial enzymes such as growth inhibitors and enzyme inhibitors and lysins and immunoglobulins (help destroy pathogens)
What is the immune system comprised of?
The innate immune system and the adaptive immune system.
When does the adaptive immune system become active?
When the attack is severe or prolonged
Where can you find macrophages in the body?
What is the name given to the vesicle formed in the phagocyte?
What is a phagolysosome?
The phagocytic vesicle that the lysosome has fused with
Describe what happens to a monocyte in the blood?
They travel around the blood for three days and enter a tissue (through cracks in the epithelieal cells of the capillary wall) where they mature into macrophages
What happens when macrophages encounter a pathogen?
They are activated, constrict blood flow away from injury site (constricts blood flow - redness)
They grow and give off chemical signals and debris from eating
What is the result of the macrophage chemicals on the epithelial cells lining the capillary?
Causes epithelial cells to contract and spaces to form between cells. Fluid leaks into the tissue and causes swelling. Also increases the recruitment of more monocytes and other immune cells - release of cytokines
What are the three states of readyness of macrophages?
Resting - small sips of their surrounding environment (low MHC 2 levels)
Primed - Larger sips when they come across something interesting (higher levels of MHC 2) - act as APC (antigen presenting cell)
Hyperactivated - they receive a strong direct signal from the pathogen
What type of phagocytic cell isn't an ACP?
Neutrophil, they are also the most abundant white blood cell
What guides the migration of neutrophils towards the site of inflammation?
Follow a trail of chemical attractants and chemokines, process known as chemotaxis
What is the immune system component for helping combat parasites?
What do the granules of eosinophyls contain?
Make histamines and herapin
What other type of cell apart from Eosinophil?
Mast cells, anaphylactic shock caused by mast cell degranulation. Contains histamine
What is the third type of cell that is derived from granulocytes?
What is compliment?
Protein in the blood that's responsible for cell killing (lysing)
What recruits and activates the compliment proteins?
The adaptive immune system
How many activation pathways exist form compliment proteins?
3 pathways, Lectin, Classical, alternative
What is the result of each activation pathways?
Lysis and opsonisation (identifying the invading particle to the phagocyte). makes a hole in the pathogen
What is the compliment protein comprised of?
Over 20 serum proteins
Which effector mechanisms which activate compliment are part of the innate immune system?
Alternative and lectin pathways are of the innate immune system?
What is the central event in the activation of compliment?
It is the proteolysis of C3, the most abundant compliment protein.
Why is the classical effector mechanism considered to be part of the adaptive immune system?
It involves the use of antibodies
When is the membrane attack complex activated?
When the c9 the final protein is bound, forms a pore in the cell
What safeguards are in place to stop compliment attacking our own cells?
Decay acceleration protein - cell surface protein in human cells - leads to break down of MAC precursor
Besides lysis, what other functions does compliment have?
Opsonisation, recruiting other immune cells (neutrophils and macrophages)
Stimulates inflammation - mast cells and neutrophils
Activates B cells and Ab production
Where do you find viruses?
Within the cell
Where can you find natural killer cells?
Blood, spleen and it then migrates to the tissue
What can natural killer cells destroy?
Tumour cells, virus infected cells, bacteria, parasites and fungi
How do the natural killer cells kill?
Bore holes in target cells by secreting perforin, MAC forms, enzymes enter the cell through the pore and cause cell suicide
FasL of NK binds to FAS of target cell and causes the target cell to commit suicide
What is the function of histamine?
Causes vasodilation, increases permeability of blood vessels, allows fluids rich in proteins to leave the capillary which causes swelling - aids blood clotting
vasodilation increases the temperature causing the metabolic rate of the cell to increase so therefore healing rate increases
Lymphocytes and phagocytes can now easily access the damaged area through the permeable blood vessels