The innate immune system Flashcards
(18 cards)
what cell lineages are involved in immunology
myeloid lineage
lymphoid lineage
what are macrophages
engulf cells via phagocytosis
signal to other cells using cytokines
antigen presenting cells
what are complement proteins
signal to other cells using C3b
for a membrane attack complex (MAC)
what are natural killer cells
signal to other cells using cytokines
induce apoptosis
what makes up the first line of defence to infection
physical barriers like skin and associated mucous membranes
what makes up the second line of defence
phagocytes
compliment proteins
natural killer cells
how does the compliment cascade get triggered
alternative pathway
classical pathway
lectin pathway
how does the alternative pathway work
occurs by chance, C3b will bind if a bacterium is close enough.
what are the three antigen presenting cells
macrophage
B cells
dendrites
how are macrophages activated
macrophages are dormant until the cytokine IFN activates it. IFN is produced by natural killer cells
what is MHC2
Major Histone Compatability complex. only antigen presenting cells produce MHC2
what are the different classes of antigen presentation
MHC1: display endogenous proteins made by that cell. tells the immune system it is a self cell.
MHC2: displays digested antigens from foreign cells
What are the characteristics of neutrophils
make up of 70% of white blood cells.
apoptose after 5 days: short life span
undergo extravasation after leaving the blood.
Phagocyte
what is the process of extravasation
the process by which a neutrophil stops at inflamed tissue and exits the blood capillary.
what are some important proteins in the complement system and what do they do
C3b: acts as an opsonoid and attracts phagocytes
C5: triggers inflammation which isolates an infection
C6-C9: form the MAC and lyse cells.
why doe the compliment system not attack self cells
all human cells have the receptor CD59 which inhibits the formation of a MAC
what are RCA and give examples of how they work
Regulatory Compliment Activation proteins (RCAs) regulate the compliment system.
Decay Accelerating Factor is a RCA that breaks down 3bBb, stopping the compliment system
other RCAs cleave C3b into an inactive form
how to natural killer cells kill cells
inject a cell with Granzyme-B which can induce apoptosis in tumour virus infected and tumour cells
The Natural Killer cell can interact with the FAS ligand on a target cell to induce apoptosis
