Innate and Adaptive Immunity Flashcards
what are cytokines?
proteins that alter the behaviour of other cells
what are chemokines?
proteins that attract other cells
what are the chemokines and cytokines, what are they made by and what do they do?
inflammatory mediators and are made by activated epithelial cells and are secreted and diffuse into the lamina propria.
they make the epithelia more permeable so things like phagocytes can migrate - all but RBCs can get in
what does the bioconcave shape of the RBCs mean?
the cell can bend so can get through small spaces.
increased cell surface to volume ratio to increase chance of gas exchange.
what are the two aspects of the innate and adaptive immune system?
humoral (dissolved) and cellular
what are the humoral aspects of the innate immune system? what do they do? Tynwald Is Legendary For All Cool Thinkers!!
transferrin and lactoferrin - deprive microbes of iron
interferons - inhibit viral replication
lysozyme - breaks down peptidoglycan in bacterial cell walls
fibronectin - oponises bacteria and promotes their phagocytosis
antimicrobial peptides
complement - cause destruction of microbes directly or with the help of phagocytic cells
TNF-alpha - suppresses viral replication and activates phagocytes and natural killer cells
what are the complement proteins, what do they do, when can they be used and what enhances the effect of them?
C1-C9.
system marks pathogens for destruction by covalently binding to their surface.
They can be used immediately after infection begins.
antibodies enhance the effect of complement activation
what is the importance of the innate immunity implied by?
rareity of inherited deficiencies in innate immune mechanisms.
considerable impairment of protection when they deficiencies do occur.
what are the cellular components of the innate immune system? what do they do? Boats Enemies Nock No More
basophils and mast cells - allergic response
eosinophils - anti-parasite and allergic response
natural killer cells - recognise and directly induce apoptosis in virus-infected/abnormal cells
neutrophils - phagocytic and anti bacterial (have several lobes to their nuclei)
macrophages and monocytes - phagocytosis and antigen presentation to lymphocytes (nuclei fill cytoplasm).
what is phagocytosis enhanced by?
coating of antibodies or complement to render it recognisable as foreign (opsonisation)
what is phagocytosis?
active engulfment of particles into a phagosome.
phagosome + lysosome (lysozyme inside) = digestion
what is the 1st event of an inflammatory response? what can it be used for?
arrival of neutrophils
marker of acute inflammation
what do mast cells do?
release inflammatory substances from granules (heparin and histamine)
how do natural killer cells induce apoptosis in abnormal cells?
pump proteases through pores they make in the target cells
what happens with the granules once the neutrophil is activated? how are neutrophils phagocytic?
unable to synthesis more granules once activated so once they have been used up the neutrophil dies.
bacteria binding to neutrophil receptors induces phagocytosis and microbial killing (lots of receptors for lots of different bacteria)
features of macrophages?
phagocytose microbial cells and damaged/unwanted cells. Release a variety of cytokines.
are long lived
generate more lysosomes as needed.
act as professional antigen presenting cells
what are the humoral aspects of the adaptive immune system and what do they do?
cytokines - promote the differentiation and proliferation of lymphocytes and natural killer cells.
perforin - released by T killer cells and destroys cell walls
antibodies - protect host by neutralisation (prevents binding to epithelia), opsonisation and complement activation (enhances opsonisation and lysis)
what are the cellular components of the adaptive immune system and what do they do?
T cells:
T helper - become activated when CD4 binds to a specific antigen on the complex of an antigen presenting cell. Once activated, clones itself to form T helper cells and T memory cells. Activates B cells and macrophages.
T killer - releases perforin when cell is already infected to kill the infected cells.
B cells - divide to form plasma cells and memory cells when activated by T helper cells and release cytokines. Plasma cells produce specific immunoglobulin (antibodies) for non-self antigens
what is opsonisation?
the coating of a microorganism by antibodies/complement to render it recognisable as foreign by phagocytes, thus enhancing phagocytosis.
the main differences between innate and adaptive immune systems
I - present from birth, A- arises from exposure to microbes
I- non specific, A- specific pathogen immunity
I- Not enhanced by 2nd exposure, A - enhanced by 2nd exposure
I- No memory, A- Acquires memory, memory cells
I- Poorly effective without adaptive response, A- poorly effective without innate immunity
what happens once the antigen is eliminated?
B and T cells undergo apoptosis. residue of B and T = seeding of memory cells
what is the process of adaptive immune response?
clonal selection clonal expansion differentiation to effector cells (T helper, cytotoxic T lymphocytes, plasma cells) elimination of antigen T and B cell apoptosis seeding of memory
what are the speeds of each type of immunity?
innate = quicker adaptive = slower however lasts much longer
what are antigens?
molecules that elicit a specific immune response when introduced into the tissues of an animal
what does clonal selection do?
induces proliferation and increase effector cell frequency
what are the receptors on T cells?
T cell antigen receptor
not membrane bound antibody but distinct molecule
what are the receptors on B cells?
surface immunoglobulin
membrane bound antibody, produces immunoglobulin, some released and some expressed on the surface.
what is the first barrier to infection and how does it protect?
epithelia. produces natural antibodies. may posses motile cilia. rapidly renewable produce cytokines and chemokines may produce mucins from goblet cells
