T Cells

Question 1

What is the specific immune response?

Answer 1

lymphocytes

Question 2

Where are lymphocytes made?

Answer 2

• in bone marrow
• T cells mature in thymus

Question 3

Why is the cell-mediated response specific?

Answer 3

• t-cells respond to antigens on the surface of specific cells which are complementary

Question 4

What are antigen presenting cells? What are the 4 types of them?

Answer 4

• any cell presenting a non-self antigen on their surface
• infected body cells present the viral antigens on their surface
• macrophage which has destroyed a pathogen becomes an APC
• cells of transplanted organs have diff. shaped antigens on surface compared to self-cell antigen
• cancer cells have abnormally shaped self-cell antigens

Question 5

Describe the cell-mediated response.

Answer 5

1. helper t-cells attach to the antigens on an APC macrophage
2. once attached/ bound, this activates the t-helper cell to divide by mitosis until a large number of clones have been made
3. the cloned t-helper cells differentiate into different cells

Question 6

What kind of cells can cloned t-helper cells become?

Answer 6

some:
-stay t-helper cells and activate b lymphocytes
- stimulate macrophages; more phagocytosis
- become memory cells for that antigen
- become cytotoxic t-cells

Question 7

What do cytotoxic t-cells do?

Answer 7

• destroy abnormal/ infected cells
• release protein, perforin, which embeds into the cell surface membrane, and makes a pore so that any substance can enter/leave the cell
  - this causes cell death
  - most common in viral infections
  - body cells sacrificed to prevent viral replication

Question 8

Explain how the function of cytotoxic t-cells can be used as an explanation for acommon sore throat.

Answer 8

• cytotoxic t-cells destroying infected body cells in throat causes pain