[5.3-4] B/T cells and cell/antibody mediated immunity

Question 1

what are the 2 types of lymphocytes?

Answer 1

• B lymphocytes (B cells)
• T lymphocytes (T cells)

Question 2

why are B cells called so?

Answer 2

• because they mature in the bone marrow
• they are associated with humoral immunity (immunity involving antibodies that are present in body fluids)

Question 3

why are T cells called so?

Answer 3

• because they mature in the thymus gland
• associated with cell-mediated immunity (immunity involving body cells)

Question 4

what are the 4 possible clones of the T cell?

Answer 4

1. killer T cell
2. helper T cell
3. suppressor T cell
4. memory T cell

Question 5

describe the process of cell mediated immunity

Answer 5

• starts when a T lymphocyte is activated by the presence of a specific antigen (protein found on the cell surface with a specific, complementary tertiary structure, as is the T cell’s receptor)
• once the immune response is activated, the T-cell undergoes rapid mitosis to increase the number of those specific antibodies

Question 6

the killer T-cell (cytotoxic T-cell)

Answer 6

• can directly destroy any non-self entity (eg. bacteria, virus)
• produces perforin, which punches holes in the outer surface of bacteria (eg.) so their contents spill out

Question 7

the helper T-cell

Answer 7

• activate other T-cells and B-lymphocytes
• initiate a chain reaction to help increase the numbers overall
• produces cytokines (signalling molecules which activate other things)
• too many cytokines to something that isn’t dangerous can be bad

Question 8

the memory T-cell

Answer 8

• basis of long term immunity
• remains in the body for a long time
  > 2 systems: blood and lymphatic
• gives you the capacity to recognise and respond to the same specific antigen much faster and on a much bigger scale than the first time

Question 9

the suppressor T-cell (don’t need to know)

Answer 9

• inhibits T and B cells’ further production
• for when you need to switch off an immune response
• immune response requires a lot of energy and cells so if you don’t need the response then the resources should be used elsewhere

Question 10

what is the 5 step process of humoral immunity?

Answer 10

1. B-cell is activated by antigens; helper T-cells also stimulate with cytokines
2. B-cell divides by mitosis and is either specialised into memory B-cells or plasma cells
3. memory B-cells remember the antigen
4. subsequent exposure to the same antigen changes them into plasma cells
5. plasma cells produce antibodies which inactivates antigens

Question 11

what is known as the primary immune response?

Answer 11

the production of antibodies and memory cells

Question 12

what are responsible for the secondary immune response?

Answer 12

memory cells

Question 13

draw and describe a graph with primary and secondary immune responses

Answer 13

• x axis = time
• y axis = scale of immune response (conc. of antibodies)
• exposure twice, differences with secondary immune response

Question 14

what are some differences between the primary response and secondary response?

Answer 14

secondary is:

• faster
• on a greater scale
• and antibody conc. stays higher for a longer amount of time

Question 15

what does the secondary immune response mean for you?

Answer 15

you may not be aware of a re-infection as the immune system deals with it before symptoms show