The immune response

Question 1

Antigen

Answer 1

A molecule (that can be a protein/glycoprotein) found on the surface of all body cells. However, foreign antigens generate immune response

Question 2

What type of foreign antigens cause an immune response?

Answer 2

Antigens on pathogens
Antigens on abnormal body cells (cancer)
Antigens as toxins
Antigens on transplanted cells from same organism

Question 3

2 types of immune response

Answer 3

Cellular response
Humoral response

Question 4

Cellular response

Answer 4

Immune response not involving antibodies but through phagocytes, cytotoxic T cells

Question 5

Humoral response

Answer 5

The targeted removal of antigens by producing antibodies by B-cells

Question 6

Phagocytosis

Answer 6

When a phagocyte engulfs a pathogen

Question 7

Stages of phagocytosis

Answer 7

Phagocyte engulfs pathogen by its cytoplasm surrounding it
Pathogen taken into cell in a vesicle (phagosome)
Fuses with lysosome = phagolysosome
Lysosomes hydrologic enzymes hydrolyse pathogen

Question 8

What happens after phagocytosis?

Answer 8

The cell can process pathogen fragments and present the antigen on its surface

Question 9

Antigen presenting cell

Answer 9

When a phagocyte presents a processed antigen after hydrolysing the pathogen to alert T-cells

Question 10

What binds to antigen presenting cells and why?

Answer 10

T helper cell that has a specific receptor complementary to the antigen
So it can be stimulated to undergo mitosis

Question 11

When are Th cells stimulated to undergo mitosis and divide?

Answer 11

After complementary receptors on Th cells bind to the specific presented antigen and cytokines are released by APC to undergo mitosis

Question 12

What does mitosis of Th cells produce?

Answer 12

Cloned Th cells with the same specific receptor which is complementary to the specific antigen

Question 13

What are the 4 uses of cloned Th cells in an immune response?

Answer 13

Stimulating humoral response
Produce memory Th
Causing increased phagocytosis
Activate cytotoxic T cells

Question 14

Step 1 of T helper cell activated humoral response

Answer 14

The cloned Th cells with specific receptor will bind to antigen presenting lymphocyte cell which can produce specific antibodies complementary to specific antigen

Question 15

Step 2 of T helper cell activated humoral response

Answer 15

T helper cells release signalling molecules detected by receptors on APC to undergo mitosis/clonal selection

Question 16

What does clonal selection of APC produce?

Answer 16

Clones of plasma cells which release the specific antibodies complementary to specific antigen to remove infection
And memory B cells

Question 17

How do plasma cells releasing antibodies remove infection?

Answer 17

Antibody bonds to 2 antigens (has 2 binding sites)
Agglutination of antigens
Which stimulates phagocytes to engulf these

Question 18

Memory B cells use

Answer 18

Has same specific antibodies complementary to specific antigen which will divide into antibody producing B cells in case of secondary infection

Question 19

Adaptation or plasma cells

Answer 19

Lots of rough endoplasmic reticulum for protein synthesis or many protein antibodies

Question 20

Use of memory T helper cells

Answer 20

Will divide to correct type of T-helper cell which is complementary to specific antigen to stimulate B cell production if reinfected for a faster secondary response

Question 21

How do cloned T helper cells increase phagocytosis?

Answer 21

By releasing cytokines for increased phagocytosis

Question 22

How do cloned T helper cells kill virally infected cells or cancer cells?

Answer 22

By stimulating cytotoxic T cells
Which kill these cells

Question 23

Active immunityc

Answer 23

When the immune system will produce its own antibodies after being stimulated to by an antigen