Why is immunology important?

Ifeoma Ezepue
Flashcards by Ifeoma Ezepue, updated more than 1 year ago
Ifeoma Ezepue
Created by Ifeoma Ezepue about 4 years ago
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University Fundamentals of Medicine (Immunology) Flashcards on Why is immunology important?, created by Ifeoma Ezepue on 10/30/2015.
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What are three reasons Why is immunology important? it underpins vaccination immunological techniques underpin many diagnostic technologies many of the diseases of the modern world are caused by the immune system going wrong
What is the basic function of the immune system? to distinguish between self and non-self
How much bacteria do we have in the gut? 10,000 species 10^14 cells
What species of bacteria can you find on the skin and in the throat? skin - staphlycocci throat - Klebsiella/Neisseria/Pneumococci
If we have all this bacteria on our skin and in our throat why are we still alive? most bacteria fine when on superficial surfaces but if get into important tissues or brain, without an immune system we can die even with an immune system they can still kill us
What is the biggest reason people with HIV die? HIV kills T-cells so patients die of opportunistic infections e.g. Pneumocystis carinii Cryptosporidium atypical Mycobacteria
What is SCID? Why is this dangerous? What treatment is available? severe combined immune deficiency lack of lymphocytes a baby with SCID may have recurrent bacterial, viral or fungal infections that are more serious and less responsive to treatment than would normally be expected bone marrow transplant needed to replace immune system
Where do the different cells of the immune system come from? the cells of the immune system come from a pluripotent stem cell circulating in the marrow
How can a bone marrow transplant be carried out? take out marrow - painful new technology: give patient drugs causing stem cells to come out of marrow and into blood harvest stem cells from blood can put into other people or back into same person
What are the different types of cells you find in the blood and immune system? Eosinophil Basophil Neutrophil Monocyte Thrombocyte Erythrocyte B cell T cell
What is hematopoiesis? the production of all types of blood cells in adults this occurs in the bone barrow and lymphatic tissues
How do pluripotent stem cells become antibodies and T cells? pluripotent stem cell lymphoid stem cell B cell and T cell B --> antibody T --> CD4 helper and CD8 cytotoxic
CD4 and CD8 cells are both major classifications of T lymphocytes. What is the difference between them? CD4 helper -carry CD4 antigens CD8 cytotoxic -carry CD8 antigens -includes cytotoxic T lymphocytes and suppressor cells
Where are T cells and B cells identified? T cells - thymus B cells - first identified in Bursa (in gut of chicken), made in bone marrow in most mammals
What are the three types of Primary lymphoid tissue? Why are they classed as 'primary'? thymus, bursa, bone marrow they work and produce cells in the absence of antigens - original source of immune cells
Give some examples of secondary lymphoid tissues tonsils lymph nodes lymphatic vessels liver spleen Peyer's patch on small intestine appendix
What are secondary lymphoid tissues? regions/organs where mature and immune competent lymphocytes colonize and function in response to antigenic stimuli
How does the immune system recognise pathogens? by responding to non-self
What is an antigen? anything which elicits an adaptive immune response self antigen - when the immune system goes awry and starts responding to self foreign antigen - when the antigen comes from outside you e.g. vaccine
What does the adaptive immune system show? In what way is the immune system and the brain similar? the adaptive immune system shows exquisite specificity the immune system has memory - when exposed to infection the body remembers this
In adaptive immunity how do immune cells respond to foreign molecules (pathogens)? using receptors which can bind to antigens antigen specific T cell receptor antigen specific B cell receptor (which is actually and antibody) massive cell division then effector function
In innate immunity how do immune cells respond to foreign molecules (pathogens)? using pattern recognition receptors and Fc receptors identify PAMPs and DAMPs -pathogen-associated molecular patterns which are associated with microbial pathogens or cellular stress and damage-associated molecular patterns which are associated with cell components released during cell damage
What are Fc receptors? How do they work? protein found on the surface of certain cells e.g. B cells, neutrophils that contribute to the protective functions of the immune system bind to antibodies attached to invading pathogens stimulates cytotoxic cells to destroy microbes or infected cells by antibody-mediated phagocytosis
What is innate immunity? the immunity that happens in the minutes or hours after infection non-specific
What are skin macrophages also known as? Langerhans cells
In health, white cells are in blood and lymph nodes and not in tissue. If bacteria were to invade the tissues how are they therefore killed? bacteria invades tissue endothelial cell cytokines (TNF-a and IL-1B) released by macrophages and increase adhesion molecules blood vessel becomes sticky neutrophil sticks on vessel, moves into tissue and kills bacteria happens within hours
The macrophage releases substances that aid in the destruction of the bacteria. However, how does the macrophage know the bacteria is there in order to produce these pro-inflammatory cytokines? the toll-like receptor molecules on the surface of mammalian cells recognise components of bacteria and viruses (PAMP) that are shared by pathogens but distinguishable from host molecules TLRs activate immune cell responses start to make pro-inflammatory cytokines there are 13 - but last three not found in humans
Give an example of TLRs and what they recognise TLR5 - flagella TLR4 - lipopolysaccharides from gram-negative bacteria
Why is pus yellow? lots of dead white blood cells major protein in neutrophil is yellow
What is a spot? inflammation and tissue injury caused by white cells leaving the blood and going into a follicle to kill skin bacteria growing in the wrong place
What is inflammation? when white cells leave the blood and move into the tissues, and in the process of getting rid of the bugs, kill normal tissue as well
How do neutrophils kill the invading pathogens? neutrophil engulfs bacteria neutrophils are full of and produce dangerous molecule -free radicals, neutrophil elastase, neutrophil collagenase, myeloperoxidase, gelatinases, anti-bacterial peptides, cytokines these may destroy normal tissues as well after neutrophils stop moving into tissue and tissues heal in ~ a week
What is ulcerative colitis? caused by massive influx of neutrophils in the colon may be identified by presence of crypt abcesses kill nasty molecules then kill epithelium cells lining gut
Use a graph to explain the differences between adaptive and defective innate immunity 1 million bugs injected IV 99% killed in first 12 hours bugs get into niche inside cell and tissue start to grow takes time as numbers so low after five days adaptive immunity happens infection can be got rid of defective innate immunity - ability to get rid of bacteria doesn't work very well, not all killed, start to grow rapidly, death by sepsis
In what way are our bodies already primed to deal with infections? at birth we already have T and B cells which can recognise billions of different foreign antigens only a few lymphocytes for each antigen they need to see and respond to pathogen quickly
What happens when a B cell becomes activated? B/T cell divides very quickly B/T cell specific to pathogen recognises it through receptor antigens B cells undergoes clonal expansions - requires T helper cells B cells become plasma B cells which produce antibodies or memory B cells - for future response T cells undergo clonal expansion controlled by IL-2 T cells mediate immunity
What happens following vaccination? after vaccinations we respond and make more lymphocytes specific for the vaccine memory cells are also primed
How does a cell know what type of cell it is? cells have thousands of different receptors to sense their extra-cellular environment receptors transmit signals from the cell surface to the nucleus to change gene expression and function
Describe the difference between the incidence of prototypical infectious diseases and that of immune disorders the former has been decreasing over time, especially following the onset of vaccines the latter e.g. crohn's disease, multiple sclerosis, asthma - has been increasing
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