Acquired continued

Question 1

Humoral immunity

Answer 1

B cells make antibodies (a y-shaped protein that neutralises pathogens)

Each antigen stimulates production of a single and specific antibody.

The B cell recognizes the different antigen on the surface of a macrophage

When a B cell meets and interacts with a specific antigen, the B cell becomes metabolically active and begins to divide.

Question 2

What are the daughter cells produced from B cells dividing

Answer 2

Plasma cells – specialised antibody factory. After 5 to 8 days it can produce thousands of
antibody molecules per second.

Memory cells – long-lived B cells that remain in lymph tissues and are responsible for the
immunity that arises following infection or vaccination. The response of memory B cells is faster and more sensitive

Question 3

Cell mediated immunity

Answer 3

To respond to most antigens, B cells need the assistance of helper T cells (TH cells).

T-cells contribute to your immune defenses in two major ways. Some help
regulate workings of the overall immune response, while others are
cytotoxic and directly contact infected cells and destroy them.

Question 4

What are the main type of T cells

Answer 4

Four main types of T cells:
– Helper T Cells
– Killer T cells
– Suppressor T cells
– Memory T cells

Question 5

Helper T cells

Answer 5

Recognise antigens on the surface of white blood cells, particularly
macrophages.
* Secrete interferon and cytokines which stimulate B cells and
cytotoxic T-cells (killer T-cells).

Question 6

Killer T cells

Answer 6

Also called cytotoxic T cells.

Destroy abnormal body cells, e.g. virus infected or cancer cells.

Stimulated by cytokines.

Release perforin which forms pores in target cells – this allows water and ions in and leads to lysis of the target cell.

Cytotoxic T cells need to recognize a specific antigen bound to self-MHC markers.

Question 7

Suppressor/Regulatory T cells

Answer 7

Suppressor T-cells or regulatory T-cells control the immune system when the antigen/pathogen has been
destroyed.

This prevents the immune system from damaging its own
cells

Question 8

Memory T cells

Answer 8

Survive a long time and can give lifelong immunity from infection.

Can stimulate memory B cells to produce antibodies.

Can trigger production of killer T cells.

Question 9

Role of antigen receptors in the immune response

Answer 9

Both B cells and T cells carry customized receptor molecules that allow them to recognize and respond to their specific targets