case 5 - immunity Flashcards
what is innate immunity
this is pre-existing immunity - naturally present
it does not amplify with repeated attacks by the same pathogen
does innate immunity have memory and is it specific
it has no memory and it is non-specific
what are the cells of the innate immune system
mast cells
basophils
eosinophils
natural killer cells
macrophages
neutrophils
dendritic cells
which 3 of these are phagocytes
macrophages
neutrophils
dendritic cells
what are the four elements of the innate immune system
physical barriers
antimicrobial factors
phagocytes and natural killer cells
inflammation and fever
what are the physical barriers
skin
respiratory tract
GI tract
eyes
what are the antimicrobial factors
complement
cytokines
iron binding proteins
anti microbial peptides
what are the cytokines - specifically interferons
interferons are released by activated macrophages and lymphocytes and virally affect cells interferon act internally in these cells and they also bind to receptor on normal cells, causing them to produce antiviral proteins. these proteins don’t interfere with the entry of the virus but they interfere with viral replication inside the cell
what is lactoferrin and what does it do
binds to iron, and in doing so it removes essential substrate required for bacterial growth
what is an example of an anti microbial peptide and where is it found
defensins - found in phagocytes
what is step one of inflammation
bacteria and other pathogens enter wound
what happens when the bacteria and pathogens enter
platelets from blood release blood-clotting proteins at wound site
what happens after platelet secretion
mast cells secrete factors that mediate vasodilation and vascular constriction. delivery of blood, plasma and cells to injured area increases
what is the next cell that is activated
neutrophils that secrete factors that kill and degrade pathogens
what do the neutrophils and macrophages do
remove pathogens by phagocytosis
what do macrophages secrete
hormones called cytokines that attract immune system cells to the site and activate cells involved in tissue repair
what is the adaptive immune system
a dedicated system of tissues, cells and molecules that act in concert to provide specific immune responses
what are the 3 cardinal characteristics of the adaptive immune responses
memory
specificity
discrimination between self and non self
what are the cellular vectors of adaptive immune response
lymphocytes
what are the three types of lymphocytes
T lymphocytes
B lymphocytes
Natural killer cytotoxic cells
what does humoral immunity involve
resistance against extracellular pathogens and the production of specific antibodies to combat these pathogens
where are B lymphocytes educated and matured
in the bone marrow
where are T lymphocytes educated and matured
the thymus gland
where are both T and B made
in the bone marrow
what are the stages of adaptive immunity
- inflammation
- phagocytosis
- T helper cell activation and clonal expansion
- B lymphocyte activation, clonal expansion and clonal differentiation into plasma
what happens in the phagocytosis stage of adaptive immunity
neutrophils - lead to B lymphocyte activation
macrophages - lead to T helper (CD4) activation
dendritic cells - lead to T lymphocyte (CD4) activation
what are the two major classes of the MHC protein
Class I and II
where is class I present
in the membranes of all nucleated cells
what does MCH I do
via the endogenous pathway, these proteins pick up intracellular peptides and present them on its surface
what happens if the cell is healthy
the T cells will ignore the cell
what happens if the cytoplasm contains abnormal peptides
If the cytoplasm contains abnormal (non-self) peptides or viral proteins, these will be presented instead by the MHC-I proteins.
what do these activate
CD8 cells
where are Class II present
only in the membranes of the macrophages and dendritic cells (antigen presenting cells)
what does MCH II do
via the exogenous pathway, these proteins pick up extracellular protein (antigens from engulfed bacteria) and present them on its surface
what is this known as
antigen processing followed by antigen presentation
what will the APC now do
travel to the lymph nodes, where they will activate CD4 cells
