11.1 Antibody production and vaccination

Question 1

What is an antigen?

Answer 1

Any foreign molecule that can trigger an immune response. The most common antigens are proteins or very large polysaccharides.

Question 2

What is blood group B?

Answer 2

Antigen H + galactose

Question 3

What is blood group A?

Answer 3

Antigen H + actylgalactosamine

Question 4

What is blood group AB?

Answer 4

Antigen H + actylgalactosamine + galactose

Question 5

What is blood group O?

Answer 5

Antigen O

Question 6

What happens if a patient is given a blood transfusion involving the wrong type of blood?

Answer 6

The immune response agglutination followed by hemolysis where the blood cells are destroyed and blood may coagulate in the blood vessels.

Question 7

What is the immune response and how does your body respond?

Answer 7

1) Pathogens are ingested by macrophages, then the macrophage displays the antigens from the pathogen’s surface on its own surface.
2) Helper T cell specific to the antigen is activated by the macrophage
3) The activated T cells then bind to lymphocytes called B cells.
4) B cell divides repeatedly to produce anti-body secreting plasma cells
5) B cell also divides to produce memory cells
6) Antibodies produced by the clone of the plasma cells (B cells) are specific to the antigens on the pathogen and help to destroy it.

Question 8

What comes first B or T cells?

Answer 8

T cells!

Question 9

What are plasma cells?

Answer 9

B cells. They are mature B lymphocytes (white blood cells) that produce and secrete a large number of antibodies during an immune response. The cell’s cytoplasm contains an unusually extensive network of rough endoplasmic reticulum (rER). rER manufactures, modifies and transports proteins, in this case, the antibodies.

Question 10

What is clonal selection?

Answer 10

The activated B cells divide many times by mitosis, generating a clone of plasma cells that all produce the same antibody type. The generation of large numbers of plasma cells that produce one specific antibody type is known as clonal selection.

Question 11

What happens after the infection has been fought?

Answer 11

The antibodies only persist in the body for a few weeks or months and the plasma cells that produce them are also gradually lost after the infection has been overcome and the antigens associated with it are no longer present.
Although most of the clone of the B cells become active plasma cells, a smaller number become memory cells which remain inactive unless the same pathogen infects the body again, in which case they become active and respond very rapidly.

Question 12

What is the role of pathogens?

Answer 12

• OPSONISATION - Antibodies make a pathogen more recognisable to phagocytes so they are more readily engulfed. Once bound they can link the pathogen to phagocytes.
• Neutralisation of viruses and bacteria - antibodies can prevent viruses from docking to host cells so they cannot enter the cells
• Neutralisation of toxins - some antibodies can bind to the toxins produced by pathogens, preventing them from affecting susceptible cells.
• Activation of complement - The complement system is a collection of proteins which ultimately lead to the perforation of the membranes of pathogens. Antibodies bound to the surface of the pathogen activate a complement cascade which leads to the formation of a “membrane attack complex” that forms a pore in the membrane of the pathogen allowing water and ions to enter the cell ultimately causing the cell to lyse.
• AGGLUTINATION - Antibodies can cause sticking together or “agglutination” of pathogens so they are prevented from entering cells and are easier for phagocytes to ingest. The large agglutinated mass can be filtered by the lymphatic system and then phagocytised. The agglutination process can be dangerous if it occurs as a result of an incorrect blood transfusion.

Question 13

What is opsonisation?

Answer 13

Antibodies make a pathogen more recognisable to phagocytes so they are more readily engulfed. Once bound they can link the pathogen to phagocytes.

Question 14

What do antibodies do to viruses?

Answer 14

They can prevent viruses from docking to host cells so they cannot centre the cells.

Question 15

What do antibodies do to toxins?

Answer 15

• Neutralisation of toxins - some antibodies can bind to the toxins produced by pathogens, preventing them from affecting susceptible cells.

Question 16

What is the activation of complement?

Answer 16

• Activation of complement - The complement system is a collection of proteins which ultimately lead to the perforation of the membranes of pathogens. Antibodies bound to the surface of the pathogen activate a complement cascade which leads to the formation of a “membrane attack complex” that forms a pore in the membrane of the pathogen allowing water and ions to enter the cell ultimately causing the cell to lyse.

Question 17

How does immunity work?

Answer 17

Immunity depends on the persistence of memory cells.
Immunity to a disease is either due to the presence of antibodies that recognise antigens associated with the disease or to memory cells that allow the production of these antibodies.
Memory cells ensure that the second time an antigen is encountered, the body is ready to respond rapidly by producing more antibodies at a faster rate.

Question 18

How do vaccines work?

Answer 18

Vaccines contain antigens that trigger immunity but do not cause the disease.
A vaccine is introduced into the body usually by injection. The vaccine may contain a live attenuated (weakened) version of the pathogen, or some derivative of it that contains antigens from the pathogen. This stimulates the primary immune response. If the actual microorganism enters the body as a result of infection, it will be destroyed by the antibodies in a secondary immune response.

Question 19

What was Edward Jenner’s experiment?

Answer 19

He noted that a milkmaid claimed that because she had caught the disease cowpox she would never develop smallpox. He infected an eight year old boy with cowpox. After a brief illness the boy recovered. Jenner then purposely infected the boy with smallpox to confirm that he had the ability to resist the disease.
He did no previous research, young boy, cant consent NOT ETHICAL.

Question 20

What is epidemiology?

Answer 20

This is the study of the distribution, patterns and causes of disease in a population.

Question 21

What is zoonosis?

Answer 21

A zoonosis is a pathogen which can cross a species barrier. The major factor contributing to the increased appearance of zoonotic diseases is the growth of contact between animals and humans by such means as humans living in close contact with livestock or disruption of habitats.

Question 22

What are histamines?

Answer 22

Mast cells are immune cells found in connective tissue that secrete histamine in response to infection. Histamine is also released by basophils which circulate in the blood. Histamine causes the dilation of the small blood vessels in the infected area causing the vessels to become leaky. This increases the flow of fluid containing immune components to the infected area and it allows some of the immune components to leave the blood vessel resulting in both specific and non specific responses.

EFFECT - Histamines cause allergic symptoms. Cells in a variety of tissues have membrane bound histamine receptors. It brings on the symptoms such a sneezing, mucus secretion and inflammation.

Question 23

What are mast cells?

Answer 23

Immune cells found in connective tissue that secrete histamines.

Question 24

What is a hybridoma cell?

Answer 24

Fusion of a tumour cell with an antibody producing plasma cell creates a hybridoma cell.

You make them by injecting the antigen into a mouse, or other mammal. In response to this challenge, the mouse’s immune system makes plasma B cells that are capable of producing the desired antibody. Plasma cells are removed from the spleen of the mouse. They will be of many different types with only some producing the desired antibody. The B cells are fused with cancer cells called myeloma cells. The cells formed by fusion of plasma B cells and myeloma cells are called hybridoma cells.

Question 25

How do you make hybridoma cells?

Answer 25

You make them by injecting the antigen into a mouse, or other mammal. In response to this challenge, the mouse’s immune system makes plasma B cells that are capable of producing the desired antibody. Plasma cells are removed from the spleen of the mouse. They will be of many different types with only some producing the desired antibody. The B cells are fused with cancer cells called myeloma cells. The cells formed by fusion of plasma B cells and myeloma cells are called hybridoma cells.

Because the full diversity of B cells are fused with the myeloma cells, many different hybridomas are produced and they are individually tested to find one that produces the required antibody.
Once identified the desired hybridoma cell is allowed to divide and form a clone. These cells can be cultured in a fermenter where they will secrete huge amounts of monoclonal antibody.

Question 26

How do pregnancy tests work?

Answer 26

Pregnancy tests use monoclonal antibodies to detect hCG. hCG is uniquely produced during pregnancy by the developing embryo and later the placenta. The urine of a pregnant woman contains detectable levels of hCG.

1) The woman washes the dye at the top of the stick down the stick with urine.
2) If there is hCG in the urine it will bind to the dye, if there is not then it wont.
3) At the first patch on the pregnancy stick, there are antibodies immobilised in the strip. If the woman is pregnant then the dye which is attached to the hCG which will attach to the antibodies which are attached to the strip meaning a coloured line will show in the first box.
4) The second box just shows if the test has worked and it has antibodies for the dye and so, if the test has worked, for both pregnant and non pregnant a line will appear.

Question 27

What is hCG?

Answer 27

Human chorionic gonadotrophin. hCG is uniquely produced during pregnancy by the developing embryo and later the placenta. The urine of a pregnant woman contains detectable levels of hCG.