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Protection against Disease Vaccination Learning Objectives Explain how vaccination helps to make you immune to diseases Starter Activity Crossword Vaccination Vaccination aims to make you immune to a disease without having to be ill A vaccine contains antigens derived from pathogenic organisms When injected into an individual the antigen stimulates a primary response that leaves memory cells to generate the secondary response (which is rapid and produces massive quantities of antibody) if the individual is subsequently infected by the relevant pathogen Adults have immunity to most common diseases (except colds and flu) This immunity is acquired through contact with the pathogen of vaccination This is called acquired active immunity and is the most effective and can last a long time Foetal Immunity During development of a human some antibodies may leak across the placenta from the mother to the foetus. Also during the first few days of breast feeding the breasts produce a high protein , low fat liquid called COLOSTRUM which contains many antibodies and provides young infant with immunity against a number of diseases until its own immune system is fully functional Antibodies are also present in later milk This is naturally induced passive immunity but no primary response occurs in baby because it is simply receiving antibodies This is PASSIVE IMMUNITY – SHORT LIVED IMMUNITY Artificial Immunity Artificially induced passive immunity arises when someone receives an injection containing an antibody- the recipient is supplied with ready made antibodies from an outside source e.g. tetanus, diphtheriaproduced/cultured in horses Natural of artificial, passive immunity only lasts a few months – the body does not produce its own antibody or memory cells since both these processes require the presence of an antigen. The antibody molecules themselves are proteins and continually being broken down and replaced Vaccines Children must receive vaccinations as they grow up to prevent large outbreaks of disease Immunisation – artificially creating immunityfirst developed by 18th century physician Edward Jenner Sometimes the original vaccine is not enough and boosters are needed In 94-95 the possibility of a measles epidemic was so high there was a big publicity campaign to ensure all school age children were immunisation Measles Measles can be very dangerous to school age children Symptoms – high temp, rash, cough , sore eyes. It can also lead to blindness, deafness and brain damage Side effects of the vaccine include a mild rash or fever for about a week and small risk of brain damage Dangers of measles far outweigh the dangers of the vaccine Types of Vaccines 1. 2. 3. 4. 5. Killed pathogens Isolated pathogens Attenuated strains Toxoids Genetically engineered antigens Killed Pathogens E.g. whooping cough vaccine is made up of killed virulent pathogens Because the cells are dead they cannot cause the disease but when they are injected the body reacts to the antigens present in the cell membranes and a primary response is induced This sort of vaccine is used against whooping cough This vaccine is injected into muscle tissue and lasts for many years Isolated Pathogens Some vaccines are made from antigen that has been isolated from the organism that produced it. The isolated antigen cannot cause the disease Some flu vaccines are of this type This vaccine is injected into muscle tissue and last for 1-3 years Attenuated strains Sometimes a less virulent strain of the pathogen is used This is usually a mutated form which does not cause the disease Such a non virulent form is called an attenuated strain. This is used to combat rubella Attenuation may be achieved by culturing the organism at a higher temp or adding specific chemicals to the culture medium This is injected subcutaneously and is permanent Toxoids With many diseases the illness is caused by the toxin that was produced by the pathogen. The toxin is often the antigen that induces the immune response Some vaccines eg for diphtheria are made of altered or modified toxin molecules that cannot cause the disease but do evoke an immune response. These are called TOXOIDS This vaccine is injected into muscle tissue and lasts for 10 years Genetically Engineered GE bacteria and yeasts are used to produce vaccines for the viral disease hep B The gene coding for the viral antigen (the virus coat protein) is cloned and inserted into bacterial or yeast cells This enable large scale production of the antigenic protein which is then purified for use as a vaccine is generated for many years When the antigen is injected into muscle tissue it stimulates the immune response and long lasting immunity is generated for many years Sometimes a person may be in a very high risk situation, for example a baby born to a mother with hep b In such case temporary immunity against hep b can be created by injecting antibody and long term immunity produce by injecting antigen at the same time Tetanus Caused by clostridium tetanus producing a deadly toxin Spores of the bacterium are found everywhere esp in soil and dust The effect of tetanus jab lasts about 10 years and a new booster is needed after Few people keep up to data so whenever a person has an accident it is vital to check up on the patient immunity Tasks
