What do these three pictures have in common?

11.1: ANTIBODY PRODUCTION & VACCINATION

Any protein identified as not self is known as an antigen

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SPECIFIC IMMUNE RESPONSE Also known as challenge and response. Challenge - antigen on the invading pathogen Response – immune response LymphocyteGeneral term for a WBC MacrophageWBC that engulf and digest Helper T cells Cytotoxic T cells B cells/plasma cells Clonal selection

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

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)

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.

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.

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.

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ROLES OF ANTIBODIES OpsonizationMaking the pathogen more visible. Neutralization of virus & bacteria Can prevent viruses from binding to potential host cells. Neutralization of toxinsAlso capable of binding to toxins, preventing the toxins from causing more harm. Activation of complementIn other words, antibodies can swarm the membrane of a pathogen, eventually causing holes/pores in the membrane leading to lyse (cell destruction). AggutinationAntibodies causing pathogens to ‘stick’ together meaning they cannot enter cells and are easier to digest.

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.

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.)

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.

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.

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?

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) iew0/chapter22/animation__ige_mediated__type_1__hyperse nsitivity__quiz_1_.html

USES OF MONOCLONAL ANTIBODIES Complete activity, pg. 475, to explain how monoclonal antibodies are used in pregnancy tests.