1. What do these three pictures have in common?
Google search results for ‘invading pathogens’

2. 11.1: Antibody production & vaccination

3. Any protein identified as not self is known as an antigen
What is the difference between self and not self?
Examples of not self? Transplanted organs, pathogens, fungus etc.
Antigens are typically proteins, or very large polysaccharides – antigens are found on the surface of wide range of different things including pollen. The body recognising these proteins as ‘not self’ triggers an immune response = allergy.
Any protein identified as not self is known as an antigen

4. Blood transfusion recap
A good example of antigens on the surface of a cell, blood transfusion.
Watch these animations in your own time, and read orange section relating to this topic on page 466/7

5. Specific immune response
Also known as challenge and response.
Challenge - antigen on the invading pathogen
Response – immune response
Lymphocyte
General term for a WBC
Macrophage
WBC that engulf and digest
Helper T cells
Cytotoxic T cells
B cells/plasma cells
Clonal selection
Can you define these terms?

6. Step 1: Macrophage
Engulf invading pathogen, digest and display antigen on their surface.
This is now an
Antigen presenting cell

7. Step 2: helper t cells
Helper T cells (lymphocyte) bind to antigens presented by the macrophages
Signaling proteins stimulate the
replication of B cells (lymphocyte)

8. Step 3: cytotoxic t cells
Cytotoxic T cells bind to antigens presented on the surface of infected cells and produced toxins which kill the infected cell.

9. Step 4: B cells
Mature B cells (once activated by helper T cells) are known as plasma cells.
B cells produce antibodies
Antibodies bind to antigens
so macrophages can easily
identify and destroy them.
Plasma cells have a large number of RER in order to swiftly produce antibodies (a protein)
These cells rapidly divide and reproduce by mitosis known as clonal selection. The new generation of B cells are clones, all producing the same antibody.

10. Step 5: memory b cells
Not all B cells become plasma cells (and then produce antibodies) some become memory cells that can survive for decades.
If a person is re-exposed to a antigen, there is a swifter/stronger immune response aka secondary immune response.

11. http://highered. mheducation

12. Roles of antibodies Opsonization Making the pathogen more visible.
Neutralization of virus & bacteria
Can prevent viruses from binding to potential host cells.
Neutralization of toxins
Also capable of binding to toxins, preventing the toxins from causing more harm.
Activation of complement
In other words, antibodies can swarm the membrane of a pathogen, eventually causing holes/pores in the membrane leading to lyse (cell destruction).
Aggutination
Antibodies causing pathogens to ‘stick’ together meaning they cannot enter cells and are easier to digest.
The different ways antibodies help to destroy a pathogen.
Diagram pg. 469

13. The principles of immunity Challenge and response
Immunity can only be developed once the immune system has been challenged by an antigen
Clonal selection
As described on previous slides, immune system selects and clones the most appropriate B lymphocyte cell
Memory cells
Provide long term immunity. Can only produce memory cells after primary infection.

14. Active Passive Production of memory cells Long-term immunity
Acquiring antibodies from another organism e.g.
Mother  foetus, through placenta. Memory cells are not transferred.
Antibodies from colostrum, again no memory cells transferred
Injection via antisera (blood serum with high antibody conc.)
Production of memory cells
Long-term immunity
Passive immunity is short term because you are not producing the antibodies yourself – you do not have the memory cells
Colostrum: breast milk produced at the end of pregnancy, low fat, high in antibodies
Examples of antisera – anti-venoms (snake/spider)

15. Immunity
We acquire immunity only when we either have the antibodies capable of recognizing specific antigens or the memory cells to produce the required antibody.
Figure 9, page 470 shows the difference between a primary and secondary immune response. Sketch this graph and describe what it shows.

16. Vaccinations
Vaccines contain antigens which trigger immunity but do not cause the disease.
Vaccines usually contain a weakened (attentuated) version of the pathogen or a derivative (something similar) with the same antigen to stimulate a primary immune response.
Check out this link in our own time.
Most famous case of a vaccination – Edward Jenner – what did he do?
Have a go at the DBQ/activity pg. 472/3

17. Histamines
Histamine is a chemical produced by mast cells & basophils in response to infection.
Histamine causes small blood vessels to dilate and become ‘leaky’  increasing the number of immune cells in a specific area.
To lessen the affects of an allergic response – antihistamines can be taken (allergy pills)
Mast cells are found in connective tissues.
Basophils are found in the blood.
Antibodies are also referred to as IgE

18. Uses of Monoclonal antibodies
Complete activity, pg. 475, to explain how monoclonal antibodies are used in pregnancy tests.
Monoclonal antibody = highly specific, purified antibody produced by clone cells. Recognize only one antigen. This

19. Epidemiology
The study of the distribution, patterns and causes of disease.
Look at the data for malaria, TB, polio or any other disease that interests you. Are there any trends you can see?

20. QUIZ next class 6.3, 11.1