Immunity Flashcards
What is the first barrier of defence for a pathogen to break through?
Epithelia.
What can epithelia produce in an immune response?
Cytokines, chemokines and natural antibodies.
What is a cytokine?
This is an agent which alters the behaviour of other cells.
What is a Chemokine?
These are chemicals which attract other cells.
Define opsonisation.
This is a process by which a pathogen becomes coated in a serum which makes it more attractive to phagocytes and therefore is engulfed.
What is the role of an inflammatory mediator?
It promotes vascular permeability, and means there is increased migration to the site of infection. This means there are increased macrophages, neutrophils and lymphocytes.
What are the signs of infection?
Inflammations which includes heat, swelling, redness and pain.
What is the innate immune response?
This is present from birth and not specific to particular pathogens. Is uses cellular and humoral immunity and is involved in triggering and amplifying adaptive immune response.
What are the two different immune responses?
Innate and adaptive.
Which immune response is enhanced on second exposure?
Adaptive
How does adaptive immunity differ from innate immunity?
Adaptive immunity is pathogen specific response.
What happens if someone is lacking an innate immune response?
The innate immune system is pretty much essential to life and this is implied by the rarity of inherited conditions. There is considerable impairment to protection when these occur.
State two cell types which have phagocytic function.
Macrophages and neutrophils.
What is a phagolysosome?
When a pathogen is engulfed it forms a phagosome, then when this fuses with a lysosomes filled with digestive enzymes it leads to a phagolysosome.
Describe the structure of a neutrophil.
Neutrophils contain granules. Once activated no more can be synthesised and so when they are all used up, the cell dies.
What can be said about a patient with neutrophil deficiency?
They are likely to suffer frequent infections.
In what two ways do macrophages help with immune response?
They release necessary cytokines, and they also act as professional antigen presenting cells to the adaptive immunity system.
What immune system are natural killer cells part of?
Natural killer cells are part of the innate immune response.
What are the two major roles of NK cells?
They kill abnormal cells such as tumours and they pump proteases into cells infected by viruses through pores.
What is the complement system in immunity?
Complements are molecules which bind covalently to the surfaces of pathogen marking them for destruction. This is then enhanced by the binding of a pathogen specific antibody.
What is the membrane attack complex?
This creates a pore in a membrane so that a complement can bind.
What are T and B cells?
These are lymphocytes and are produced from a common lymphoid precursor.
What is the role of a T helper cell?
These activate B cells and macrophages.
What is a B lymphocyte?
This is also known as a plasma cell. These are antibody producing.
Where are T and B cells found?
These are inactive, and travel in the blood. They are activated when an antigen binds.
What is meant by the clonal nature of the adaptive immune system?
This means that because each lymphocyte displays a different antigen specific receptor, there must be many different ones, with each one being a progenitor of a clone of daughter cells.
What is the problem with clonal distribution?
Lymphocytes of the required specificity are normally too infrequent to mount an effective immune response. Clonal selection rises this frequency of cells of particular antigen specificity
How does the immune system recognise differences between host and pathogen?
It looks for differences in amino acid sequence.
