Immune system Flashcards
Active immunity
Your body protects itself against microorganisms by producing antibodies
Passive immunity
The body doesn’t produce the antibodies itself but is given. For example through vaccine or the placenta from a mother to a baby.
Pathogen
A microorganism that causes disease
Bacteria
A small microorganism that is a prokaryotic cell. Singled celled organism.
Eliza method
Place the antigens into the well and they should bind to the plastic coating. Then add the primary antibody. Then wash away any unbound antibodies. Then add the secondary antibody which should have a colorimetric tag.. Then wash away any unbound antibodies. Then add the substrates. If the test is positive a colour change should take place. The stronger the colour change the higher the concentration of antibodies which can be identified with a spectrometer.
Elisa definition
Stands for Enzyme linked immunosorbent assay. Uses enzymes and colour change to identify a substance, metabolite (disease) or surface marker. It uses antibodies to identity and quantitate protein.
Radioimmunoassay RIA method
A quantity of antigen is made radioactive by labelling it with gamma radioactive isotopes of iodine attached to tyrosine (amino acid). The radiolabelled antigen is then mixed with a known quantity of antibody complementary for that antigen. The two chemically bind together. A sample containing a unknown quantity of that antigen is added. This causes the unlabelled antigen from the serum to compete with the radiolabelled antigen for the antibody binding site. As the concentration of unlabelled antigens increase more complexes form, displacing the radiolabelled variable. The bound antigens are then separated from the unbound antigens and the radioactivity of the free antigen remaining in the supernatant is measured.
Radioimmunoassay RIA definition
Uses antibodies to detect and quantitate the amount of antigen present in a sample. The test is highly sensitive detecting low quantities. the radioactive antigens (known as tracers) compete with non-radioactive antigens for a fixed number of antibodies or receptor binding sites so this test is highly specific.
Worms
Flat, ribbon like organisms that can live inside the gut if a newly hatched worm or egg is ingested.
Prions
Misfolded proteins which cause a change in shape. One miss fold can lead to other proteins changing shape too. This can transmit between people (communicable) The change to the primary structure of proteins can cause cells not to function.
Protozoa
Similar to bacteria but much bigger and have a nucleus. A similar cell organism. They are motile and feed on organic matter.
Virus
Smallest of organisms containing just a strand of RNA or DNA and a protein coat. It is a parasite so only causes harm and reproduce once inside a host cell.
Antigens
Cause disease and is identified as foreign causing an immune response. Made up of protein and glycoprotein that are present on the cell surface.
Cell mediated response
Made up of T lymphocytes. T helper cells identify a foreign pathogen stimulating phagocytes, B-lymphocytes and cytotoxic T cells. Cytotoxic T cells (effector cells) produce toxins which lysis the pathogen. Effected cells display fragments of the antigens on the cell surface to signal that they need to be lysis.
Humoral response
B Lymphocytes are activated by T helper cells when a foreign pathogens are identified. This takes place in the bone marrow. Plasma cells identify the correct antibody for the antigen to form the specific complex at the binding site and replicate flooding the bloodstream with the antibody. The antibodies then clump to the antigen. This deactivates the antigen and signals with cytokines to phagocytes (increasing phagocytosis rate) and cytotoxic t cells that it needs to be lysis. Some plasma cells remain in the blood even after the pathogen has gone. These become memory cells so that is the pathogen is encountered again the correct antibody can be replicated much quicker preventing you from getting ill.
