lecture 7 animal Flashcards
what two types of immunity are there
innate and adaptive
innate immunity – what kind of animals – what is it
all animals
– recognition of traits shared by BROAD ranges of pathogens – uses small set of receptors
– rapid responsea
adaptive immunity – what kind of animals – what is it
only vertebrates
– recognition of traits SPECIFIC to particular pathogens – using VAST ARRAY of receptors (lock and key)
– slower respponse
how many lines of defense are there and what are they
3 lines
–first line – barrier defenses
– second line – internal defenses
– third line – humoural response (adaptive)
barrier defenses (vague examples
skin, mucous membranes, secretions
internal defenses (vague examples)
phagocytic cells, natural killer cells, antimicrobial protiens, inflammatory response
humoural response – vague
antibodies defend againts infection in body FLUIDS
cell-mediated responses vague
cytotoxic cells defend against infection in body cells (alread infected w virus)
barrier defenses prevent..
most pathogens from entering the body
skin/shells/cuticles first line barrier –
thickened outer surface inhibits entry by pathogens
mucous membranes first line barrier
mucus secreted by internalized EXTERNAL surfaces (internal surfaces of nose, mouth – facing outside) – traps microbes and other particles – prevents from replication
secretions – saliva, tears – barrier
washing away – prevents microbial colonization – also hostile chemical environemtn to pathogens – lysozyme and acdic pH
phagocytic cells – recognize ..
molecules characterixtic of a set of pathogens – the molecule that is recognized has to be one of the things the virus needss for survival but is absent in our own bodies
why is it important for the componewnt to be essential to the pathogen
so the pathogen does not adapt into something unrecognizeable through natural selection
what type of blood cell are phagocytic cells
white blood cell
phagocytic cells destroy pathogens by..
phagocytosis – eating the foreign object
where are phagocytic cells located
blood, skin, mucous membrane, lymph
basic run down of what phagocytic cell does
detects pathogen floating in fluid, envelops the pathogen and turns into vacuole – fuses with a lysosome which contains digestive enzymes – pathogen will be digested and expelled out of cell
lymphatic system – vessels
interconnected closely with capillaries – circulatory system
lymphatic system – nodes
the inflammation of nodes indicates body is fighting off infection
– stores defensive cells (macrophages)
what do the defensive cells stored in lymph nodes have to go through
to get tp the infected area, have to go through capillary system – with help of lymph vessels
rundown of the lymphatic systen (cut)
lymphatic system is responsible for bringing fluid back to circulatory system after your cut – because of leaked blood – cut may have enabled pathogens to enter so lymphatic system will recirculate blood and also check for pathogens
natural killer cells recognize –
surface proteins of virus infected cells – cells that have already been infected
what do natural killer cells do after they recognize infected cell
release chemicals ghat cause apoptosis (cell death) in the infected cell
antimicrobial proteins – role
attack pathogens or prevent their reproduction
two types of antimicrobial proteins
interferons and complement proteins
interferons what are they and what do they do
secreted by virus infected cells – these proteins will be released toneighbouring cells which will trigger those neighbouring cells to produce chemicals that inhibit viral rewpropduction
complement proteins what are thry and what do they do
are plasma proteins that are activated by substances on the surface of many microbes
– when they are activated they work together and bcome a structure that embeds in membrane of pathogen to allow proteins to go through an lyse the pathogen
what are complement proteins also involved in
inflammation and adaptive immunity
inflammatory response
swelling, redness, fever..
signalling molecules released by white blood cells by injured or flue infected tissue that causes local inflammation (sore throat)
Two types of signalling molecules
histamine, cytokine
histamin – vague
triggers vasodilation (dilation of blood vessels) – and triggers increased blood permeability in affected area
– therefore more white blood cells and proteins can enter the intersitial fluid area
cytokines – vague
further increases the blood flow to the affected area when histamine dilates blood vessel
signalling molecules cause..
capillaries to dilate (histamines) and increase blood flow (cytokines)
what cells work together to fight the infection (think phagocytic ..)
neutrophils, activated complement proteins, antimicrobial proteins arriving from the blood
basic run down of how signalling molecules work (splinter example)
splinter makes way through skin – passes through first barrier – carries pathogens with it – white blood cells like macrophages and masts release signalling molecules (histamine) to dilate blood vessels which signals cytookne to increase blood flow – the combination of them allow more macrophafges to come into area (phagocytic cells which will engulf pathogens)
inflammatory response – serious flu
can cause systemic inflammatory response (fever – whole body) – therefore the release of MORE white blood cells from bone marrow is needed – resets body’s thermostat which causes fever
hypothesis that comes from the resetting of the body’s thermostat
enhances phagocytosis – or the increase in temperature can s[peed of the enzymatic reactions to produce even more white blood cells
adaptive immunity involves what type of recognition
pathogen specific
for adaptive immunity specificity is achieved through interactions between what two things
antigens and antigen receptors
antigens
large molecukes found on the surface of the specific pathogens or are secreted by the pathofen
antogen receptors
proteins produced by B and T cells
what type of cells are B and T cells
white blood cells
an epitope is..
a small accessible portion of an antigen that binds to antigen receptor
lymphocytes are what and produc ed where
are white blood cells and produced in the bone marrow
B and T cells mature where
B cells mature in the bone marrow –
T cells migrate to the thymus for maturation
what do B and T cells have in common
each B and T cell produces a SINGL type of antigen receptor that differes from each other
each antigen receptor buindfs to a single epitope of a single antigen
what regions of antigen receptors produce the specificity of the antigen binding site
1variable regions (tips of the structure that have variability for binding site for verys specific epitope
what cell (B or T) is responsible for humoural response
B cells
what happens during humoural response – vague outline
B cell antigen receptors will bind to intact antifens in the blood or lymph – these antigens may be on the surfsace of the pathogen or secreted by them
what cell B or T is responsible for cell mediated response
T cell
what happnes during cell mediated resposne – vague outline
T cell antigen receptor can only bind to antigen FRAGMENTS presented on the surface of host cells
– pathogen will infect the host cell and take over – will have antigen fragments floating around – molecule and fragmewnt will bind – go to surface of host cell – and “flag” down T cell which will have the specific antigen receptor for that fragment
B and T cells do what when they encounter their specific epitope
proliferate – replicate themselves with the same type of binding site once they encounter that specific epitope
what two types of cells occur from proliferation
memory cells and effector cells
effector cells – characteristics
short lived cells that take effect immediately against pathogen or antigen
memory cells characteristics
long lived cells that give rise to effector cells if the same epitope is encountered again
effector forms of B cells are..
plasma cells which secret antibodies
antibodies are.
soluble forms of antigen receptors – specific for the same epitope as the orginial B cell
once you release these antibodies into your bloodstream..
they will find floating pathogens and will match up specificallt to epitope and mark the pathogens for inactivation or destruction
antibodies – inactivation
neutralization prevent spathogen entry into cells and toxins can also be neutralized by antibodies
antibodies – destreuction
antibody binding increases the ability of phagocytic cells to recognize pathogens – leads to increase phagocytosis of pathogens
antibodies activate what other form of destruction
complement system – leading to PORE formation
complement system leading to pore formation – antibodies – example
complement protein will recognize forein cell – will get activated and form complex that will create holes/tubes across membrane of pathogen and will lyse the cell
effector forms of T cells are
helper T cells and cytotoxic T cells
what is the broad outline that happens when effector forms of T cells find pathogen
the infected cell will have a fragment tag – The helper T cell’s antigen receptor will bind to the antigen fragment – which will help activate B cells and cytotoxic T cells
– B cells and cytotoxic T Cells are activated by cytokines from the Helper T cells
– the cytotoxic t cells secrete proteins that will lead to cell dwath in the infected cell
cytotoxic cells bind to the infected ce3lls and secrete what two proteins
perforin and granzymes
perforin causes
pores to form in the cell membrane of infected cells – cell will brust/lyse
granztmes initiate
apoptosis
memory cells, produced during the original ……
B cell or T cell proliferation, will give rise to effector cells if the same epitope is encountered agsain – secondary immune response which will be rapid
