Topic 11.1 - Antibody production and vaccines

Question 1

Antigens

Answer 1

Every organism has unique molecules on the surface of their cells. Any foreign molecule that can trigger an immune response -> antigen

Most common antigens are proteins and large polysaccharides.

Influenza virus has the hemagglutinin protein that binds to the surface of host cells.

Question 2

Antigens in blood transfusion

Answer 2

Antigens on red blood cell surface stimulate antibody production in a person with a different blood group.

ABO and Rh blood group are important antigen systems.

(Look at sheet/ page 466 showing additional molecules that make up antigens)

Question 3

Wrong transfused blood

Answer 3

Since blood contains the antibodies for blood that is not the group that the body has (for example blood type O has antigens against A and B antigens), any incorrect blood groups will be destroyed.

The antibodies (IgM) are pentamer: they attach to 5 blood cells at once. These antibodies then cause agglutination - where blood cells clump up together. This could block blood vessels and be fatal.

Question 4

Immunoglobulins

Answer 4

igM
igG
igA
igD
igE

Question 5

Specific immune response

Answer 5

Macrophages consume the pathogen and display the antigens of the pathogen on its surface (APC - antigen-presenting cell).

T helper cells then try to attach to the antigen and the T helper cell with the correct complementary antigen bind to the macrophage and becomes activated.

This activated T helper cell then attaches to the complementary B lymphocyte which is then activated to become either a memory cell or plasma cell, with plasma cells releasing antibodies against the pathogen.

Question 6

Plasma cells

Answer 6

Plasma cells are produced by B lymphocytes becoming activated and since they manufacture, modify, and transport proteins, they have many rERs.

They also have dark staining because of large numbers of unexpressed genes. There are large numbers of unexpressed genes as these cells only and repeatedly produce the same type of protein.

Plasma cell creation is called clonal selection because there are many clones of the same type of cell that produces the same specific antibody.

Question 7

Memory cell formation

Answer 7

After the infection is finished, plasma cells slowly disappear and are lost. Despite this, being infected by that pathogen rarely occurs as memory cells are present.

During plasma cell formation, a small number of memory cells are formed. These cells remain in the body for a very long time and remain inactive until the pathogen with their complementary antigen is present.

If the pathogen enters the body again, the memory cells reactivate and the antibodies to destroy the pathogen are produced quickly. This is how immunity works.

Question 8

Role of antibodies

Answer 8

Antibodies aid in the destruction of pathogens in many ways: Opsonisation, neutralisation, activation of complement, and agglutination.

Question 9

Opsonisation

Answer 9

Pathogen becomes more recognisable to phagocytes which can then consume the pathogen quicker and easier.

Question 10

Neutralisation

Answer 10

Antibodies can bind to viruses or toxins to prevent viruses from docking to host cells or toxins from attacking susceptible cells.

Question 11

Activation of complement

Answer 11

Complement system is a collection of proteins that lead to the perforation of membranes. The complement cascade is triggered by proteins which create a membrane attack complex. A membrane pore is opened and water and ions flood into the cell, causing it to lyse.

Question 12

Agglutination

Answer 12

Pathogens are clumped together (usually by IgM antibodies as they are pentamer) and prevented from attacking cells and are also made easier to be consumed by phagocytes.

Question 13

Immunity

Answer 13

Caused by having memory cells against that pathogen. First immune response -> takes a while for the pathogen to be destroyed and antibodies take a while to be produced.
Secondary immune response -> Pathogen destroyed quickly and antibodies produced extremely rapidly, also more produced than in primary response.

Types of immunities -> active and passive

Question 14

Active immunity

Answer 14

Caused by being creating your own memory cells. Example is being infected by the pathogen and creating your own defence and memory cells.

Question 15

Passive immunity

Answer 15

Caused by receiving the memory cells from another source. Example is receiving memory cells through breast milk.

Question 16

Inflammation

Answer 16

Caused by phagocytes moving towards an infected area and causing swelling.

Question 17

Vaccines

Answer 17

Put an attenuated version of the pathogen in the body so that immunity can be easy and relatively harmless.

Question 18

Smallpox

Answer 18

First infectious disease eradicated by vaccines.

Question 19

Zoonoses

Answer 19

Infectious diseases that can cross the species barrier. Examples include fever, bird flu, Lyme, and West Nile.

Question 20

Histamines

Answer 20

Produced after basophils release it after detecting allergic substances or by mast cells after detecting infection.

Causes dilation of vessels in the infected areas, supplying more of the immune response substances, triggering both specific and non-specific responses. Also causes allergy symptoms and possibly even anaphylaxis.

Question 21

Hybridoma cells

Answer 21

Result of a fusion cell with an antibody-producing cell.

Antigen injected into mouse -> immune system creates b lymphocytes -> spleen removed and lymphocytes obtained -> lymphocytes fused with myeloma (cancer) cells -> These cells are hybridoma cells.

Hybridoma cells can be used to mass-produce a particular antibody.

Question 22

Monoclonal antibodies

Answer 22

Antibodies formed by hybridoma cells.

Diverse b cells in the spleen - leads to many types of hybridoma cells being produced. After the correct hybridoma cell has been identified, putting the hybridoma cell in a fermenter can cause the mass-production of the monoclonal antibodies.

Used for both treatment and diagnosis: HIV, Malaria, and pregnancy tests for example.

Question 23

Monoclonal antibodies in pregnancy tests

Answer 23

During pregnancy, hCG (human chorionic gonadotrophin) is produced and by using monoclonal antibodies for hCG, pregnancy can be detected.

Urine interacts with the test kit -> if hCG is present, it binds to hCG antibodies that are bound to a dye -> the fluid moves down further where there are immobilised hCG antibodies and they react with any hCG, removing the dye and making a stain -> fluid moves down to the bottom of the kit and leftover antibodies react with immobilised antibodies, producing dye.

If hCG is not present, it doesn’t bind at the first dye producing site. However, the last site is a control site and should always produce dye to show that the test is working.

Question 24

Neutrophils

Answer 24

Normal value blood %: 54-62
Function: Kill and digest bacteria and fungi, first step in immune response.
Elevated levels may mean: bacterial infections, stress.

Question 25

Eosinophils

Answer 25

Normal value blood %: 1-3
Function: attack parasitic or cancer cells, helps with immune response.
Elevated levels may mean: allergic, parasitic worms, autoimmune responses