Immunity Flashcards
Immunity
the ability of an organism to resist an infection or toxin
Features of an effective immune system
Fast/rapid, should not harm the host, response should be innate, must be an appropriate response for the pathogen
Active Immunity
Body produces antibodies because of an immune response to a foreign antigen. Results in production of B memory cells. .
Natural active immunity
Gained due to the infection of a pathogen (e.g. Getting a cold)
Memory T cells remember foreign antigen for long periods of time
Memory B cells will rapidly divide into plasma cells to produce many antibodies
Artificial active immunity
Via vaccination
Antigens are artificially introduced, usually as an attenuated virus (i.e. An inactive, weaker version of virus), or only parts of the pathogen that has the antigen
Purpose is to generate B memory cells which will then divide into plasma cells to produce antibodies.
Passive Immunity
Short lives as your body is being injected with antibodies, thus B memory cells will not be produced
Natural passive immunity
Antibodies are not produced in the body but from an outside, natural source (e.g. breastmilk)
Artificial passive immunity
Antibodies are given as an injection (e.g. snake anti-venom)
Herd Immunity
Indirect protection from infection. Protection is created by the presence of immune individuals in population, gives those who are unvaccinated from the disease protection.
Highly beneficial to infants and HIV patients.
Infants have immature immune systems which cannot produce enough B and memory T cells which may reduce their ability to be vaccinated.
Monoclonal Antibodies in Treating Cancer
Antibodies can be designed that target antigens on cancer cells, and then multiple copies of these antibodies can be produced in a lab
MABs used in cancer treatment can be divided into two groups;
1. Naked MAbs: which do not have any other molecules joined to them
2. Conjugated MAbs: have additional groups attached
Naked MAbs uses
stopping growth of new blood vessels to cancer, signalling immune cells to attack cancers, blocking signals for cell division
Conjugated MAbs uses
delivering anticancer drugs to cancer cells, delivering radioisotopes to cancer cells
Hypersensitivity
occurs when the immune system is activated when it doesn’t need to be
Type 1 hypersensitivity
Allergic response
Abnormal reaction to a normally harmless substance
First Exposure
Allergen - (i.e. An antigen that causes the immune system to act in an abnormal way) lodges in mucus membranes and is recognised as foreign by immune system
Immune response occurs and plasma cells produce vast quantities of IgE
IgE detect and travel to a special white blood cells known as mast cells (does this by identifying the Fc portion of the cell)
Second Exposure
Allergen travels and binds to the specific IgE antibodies that are already bound to mast cells
This causes mast cells to release vast quantities of histamine which has several effects/symptoms on the body (e.g. redness and swelling, watery eyes, sneezing)
Type 2 hypersensitivity
Autoimmune Disease
When either the humoral or cell mediated immune response is activated against the self-cells of the host, often leading to damage of the affected tissues/organs.
Examples include: type 1 diabetes, MS
Immunodeficiency
Whereby functioning of innate and/or adaptive immune response is impaired
Leads to increased vulnerability of infection
HIV/AIDS
Virus that specifically invades and destroys T helper cells, thus leads to progressive impairment of the immune system given the major roles T helper cells play (i.e. clonal expansion of B cells and release of cytokines to activate cytotoxic T cells)
People who are HIV positive, if left untreated, will exhibit progressive loss of T helper cells > this in turn results in the immune response being unable to fight pathogens causing HIV to be referred to as AIDS
Pathogens
anything that can cause disease. Impairs normal functioning of its host
Viruses
Obligate intracellular parasites, non-cellular and non-living.
Cannot independently reproduce - needs to infect a cell and use that cells
Bacteria
Causes disease, cellular agents, can reproduce independently via binary fission.
Natural flora is beneficial because they compete with pathogenic bacteria for resources
Fungi
Eukaryotes, have a chitin cell wall, acts as infectious agents
Prions
Misfolded proteins, converts normal prion proteins into an abnormal form, build-up in neurons, causing neuron to burst
Antigens
compounds, usually proteins, that can trigger the immune system to respond in various ways, found on the outside
B cells
mature in bone marrow then to lymph nodes
T cells
produce in bone mature, mature in thymus gland then travels to lymph nodes
