Compare and contrast the primary and secondary immune responses ; Compare and contrast active, passive, natural and

1. 2.2.2 Health and Disease • Compare and contrast the primary and secondary immune responses; • Compare and contrast active, passive, natural and artificial immunity; • Describe, with the aid of diagrams, the structure of antibodies; • Outline the mode of action of antibodies, with reference to the neutralisation and agglutination of pathogens;

2. How immunity develops • During the body’s first encounter with a pathogen there will be few lymphocytes with specific receptors • It takes time to divide to form clones, B lymphocytes to secrete antibodies, T lymphocyte production • If the same pathogen invades again persisting memory cells can give a faster, more effective response

3. This is ACTIVE IMMUNITY Secondary response happens more quickly, and produces many more antibodies

4. Natural immunity: active and passive • An infection is an example of acquiring natural immunity. It is called ACTIVE as your body needs to work to produce the necessary antibodies • When a mother breast feeds her baby she passes antibodies to it. This is a way of acquiring PASSIVE immunity as it is a way of gaining antibodies without the immune system having to produce them. The thick, yellowish milk (colostrum) that is produced for the first few days after birth is particularly rich in antibodies.

5. Artificial immunity: active and passive • An alternative to natural immunity developing is to give vaccinations (artificial immunity) • Antigen is injected into the body. This may be in the form of an inactivated bacterial toxin or attenuated (not harmful) virus which would promote ACTIVE immunity; • or the injection of antibodies or antitoxins which would promote PASSIVE immunity (eg Clostridium tetani)

6. Passive immunity • Passive immunity doesn’t last as long as active immunity (only weeks or months): • No lymphocytes are stimulated to clone themselves • No memory cells have been made • This type of immunity can only last as long as the antibodies/toxins last in the blood

7. Antibodies • Antigen binds with variable region (specific) • Have disulphide bonds between different chains of the antibody • Also known as “immunoglobulins” shortened to Ig such as IgA or IgE • Different immunoglobulins respond to antigens in different ways…

8. Antibodies • Neutralisation: bind with bacterial toxins • Agglutination: make pathogen clump together • Phagocytosis: often follows agglutination

9. 2.2.2 Health and Disease • Explain how vaccination can control disease • Discuss the responses of governments and other organisations to the threat of new strains of influenza each year • Outline possible new sources of medicines, with reference to microorganisms and plants and the need to maintain biodiversity

10. 2.2.2 Health and Disease • Compare and contrast the primary and secondary immune responses; • Compare and contrast active, passive, natural and artificial immunity; • Describe, with the aid of diagrams, the structure of antibodies; • Outline the mode of action of antibodies, with reference to the neutralisation and agglutination of pathogens;

11. How immunity develops • During the body’s first encounter with a pathogen there will be few lymphocytes with specific receptors • It takes time to divide to form clones, B lymphocytes to secrete antibodies, T lymphocyte production • If the same pathogen invades again persisting memory cells can give a faster, more effective response

12. This is ACTIVE IMMUNITY Secondary response happens more quickly, and produces many more antibodies

13. Natural immunity: active and passive • An infection is an example of acquiring natural immunity. It is called ACTIVE as your body needs to work to produce the necessary antibodies • When a mother breast feeds her baby she passes antibodies to it. This is a way of acquiring PASSIVE immunity as it is a way of gaining antibodies without the immune system having to produce them. The thick, yellowish milk (colostrum) that is produced for the first few days after birth is particularly rich in antibodies.

14. Artificial immunity: active and passive • An alternative to natural immunity developing is to give vaccinations (artificial immunity) • Antigen is injected into the body. This may be in the form of an inactivated bacterial toxin or attenuated (not harmful) virus which would promote ACTIVE immunity; • or the injection of antibodies or antitoxins which would promote PASSIVE immunity (eg Clostridium tetani)

15. Passive immunity • Passive immunity doesn’t last as long as active immunity (only weeks or months): • No lymphocytes are stimulated to clone themselves • No memory cells have been made • This type of immunity can only last as long as the antibodies/toxins last in the blood

16. Antibodies • Antigen binds with variable region (specific) • Have disulphide bonds between different chains of the antibody • Also known as “immunoglobulins” shortened to Ig such as IgA or IgE • Different immunoglobulins respond to antigens in different ways…

17. Antibodies • Neutralisation: bind with bacterial toxins • Agglutination: make pathogen clump together • Phagocytosis: often follows agglutination

18. 2.2.2 Health and Disease • Explain how vaccination can control disease • Discuss the responses of governments and other organisations to the threat of new strains of influenza each year • Outline possible new sources of medicines, with reference to microorganisms and plants and the need to maintain biodiversity

19. Vaccinations • Most vaccinations given by injection eg meningitis C, BCG, MMR • Some oral eg Polio • Most contain attenuated virus or bacterial toxins and offer artificial active immunity

20. Herd immunity: At least 80-85% of the population need to be vaccinated to reduce the chance of somebody catching the disease – even some one who has not been vaccinated- to safe levels.

21. Vaccinations

22. The MMR controversy • Hit the headlines in 1998 that the combined MMR vaccine showed possible links with autism • Later rejected by respected scientists in 2004 but the damage had been done

23. The threat of new disease • There is a constant threat of new infectious diseases emerging TASK: make notes from page 186-8 noting important dates and events in the tracking of these diseases: • SARS: severe acute respiratory syndrome • New strains of flu (eg H5N1)

24. Sources of new drugs • There is a continual need for new drugs and antibiotics • Around 7000 prescription drugs in the UK are derived from 3000 plant species, many of which are found in tropical rain forests • For this reason among others it is important to preserve the rain forest’s biodiversity • There are issues about large drugs companies making lots of money from plants discovered and used for centuries by native tribes

25. Sources of new drugs • The study of the use of plants by native people has become known as “ethnobotany” • Foxgloves contain a poison called digitalin which can be used to treat irregular heart rhythms (cardiac arrhythmias) • Quinine used to treat malaria was first discovered in the bark of trees in Peru when locals were seen using it to treat fever

26. Vaccinations • Most vaccinations given by injection eg meningitis C, BCG, MMR • Some oral eg Polio • Most contain attenuated virus or bacterial toxins and offer artificial active immunity

27. Herd immunity: At least 80-85% of the population need to be vaccinated to reduce the chance of somebody catching the disease – even some one who has not been vaccinated- to safe levels.

28. Vaccinations

29. The MMR controversy • Hit the headlines in 1998 that the combined MMR vaccine showed possible links with autism • Later rejected by respected scientists in 2004 but the damage had been done

30. The threat of new disease • There is a constant threat of new infectious diseases emerging TASK: make notes from page 186-8 noting important dates and events in the tracking of these diseases: • SARS: severe acute respiratory syndrome • New strains of flu (eg H5N1)

31. Sources of new drugs • There is a continual need for new drugs and antibiotics • Around 7000 prescription drugs in the UK are derived from 3000 plant species, many of which are found in tropical rain forests • For this reason among others it is important to preserve the rain forest’s biodiversity • There are issues about large drugs companies making lots of money from plants discovered and used for centuries by native tribes

32. Sources of new drugs • The study of the use of plants by native people has become known as “ethnobotany” • Foxgloves contain a poison called digitalin which can be used to treat irregular heart rhythms (cardiac arrhythmias) • Quinine used to treat malaria was first discovered in the bark of trees in Peru when locals were seen using it to treat fever