Secondary non-specific and immune responses

Question 1

What are the two types of phagocytes?

Answer 1

Neutrophil and Macrophage.

Question 2

What are the features of a neutrophil?

Answer 2

Small, quick, die when finished.
Granular/thick cytoplasm.
Multi-lobed nucleus for squeezing through pores.

Question 3

What are the features of a macrophage?

Answer 3

Large, long lasting.
Release interleukin. (a cytokine)
Antigen-presenting cells.

Question 4

What is the mechanism by which macrophages present antigens?

Answer 4

Partially digested foreign body is combined with the MHC (Major Histocompatibility Complex) and presented on the cell surface membrane, activating the specific immune response.

Question 5

What is chemotaxis?

Answer 5

The movement of phagocytes towards chemicals produced by the pathogen/platelets/(cytokines).

Question 6

What is a phagosome?

Answer 6

The vesicle formed around a particle engulfed by a phagocyte via phagocytosis.

Question 7

What is a phagolysosome?

Answer 7

When a lysosome fuses with a phagosome, destroying the ingested pathogen.

Question 8

Outline the process of phagocytosis.

Answer 8

Chemotaxis, phagocytosis (pathogen engulfed) forming a phagosome, lysosome fuses forming a phagolysosome. The indigestible material is then discharged.

Question 9

What releases cytokines?

Answer 9

Phagocytes.
Mast cells.
T-helper cells.

Question 10

What do cytokines do?

What is an example of a cytokine?

Answer 10

Attract phagocytes, increase temperature, activates specific immune response.
Interleukin is an example of a cytokine.

Question 11

What do opsonins do?

Answer 11

Antibodies are opsonins.

Opsonins bind to antigens on antigen-presenting cells, making recognition by phagocytes easier.

Question 12

What is the first step of the immune response?

Answer 12

Pathogen engulfed by phagocytes and antigens presented on the surface of the macrophage.

Question 13

What does the presenting of antigens by macrophages cause?

Answer 13

Clonal selection of correct T-killer and T-helper cells.

Question 14

What is clonal selection?

Answer 14

Exposure to a specific antigen selectively stimulates the differentiation of cells with the appropriate antibody.

Question 15

What is clonal expansion?

Answer 15

Mass proliferation of lymphocytes by mitosis.

Question 16

What are the 2 types of lymphocytes?

Answer 16

B and T lymphocytes.

Question 17

Where are B-lymphocytes produced and where do they mature?

Answer 17

Both in the bone marrow.

Question 18

Where are T-lymphocytes produced and where do they mature?

Answer 18

Produced in the bone marrow, mature in the thymus gland.

Question 19

What response do B-lymphocytes produce?

Answer 19

Humoral response.

Question 20

What response to T-lymphocytes produce?

Answer 20

Cell mediated response.

Question 21

What are the different types of B-lymphocyte and what do they do?

Answer 21

Plasma cells (produce antibodies).
Memory cells (provide immunological memory).

Question 22

What are the different types of T-lymphocytes and what do they do?

Answer 22

T-killer cells (kill pathogens).
T-regulator cells (stop immune response when pathogen is dead, preventing auto-immune response).
T-memory cells.
T-helper cells (release interleukin and activate B-cells).

Question 23

How do T-killer cells destroy the pathogen?

Answer 23

They search for infected cells, attach to them and secrete toxic substances (hydrogen peroxide) into the cell, killing the pathogen.

Question 24

What happens after the B-lymphocytes are activated by interleukin released by the T-helper cells?

Answer 24

Clonal selection and clonal expansion of B-cells, causing them to differentiate into plasma cells and memory cells.

Question 25

What do B-cells require to be activated?

Answer 25

Interleukin and free antigens.

Question 26

What is an autoimmune disease?

Answer 26

When the immune system no longer recognises “self” cells and attacks them.
(an individual’s own body cells are antigenic)

Question 27

How are autoimmune diseases treated?

Answer 27

With immunosuppressants, however, this leaves the patient vulnerable to infection.

Question 28

What are some examples of autoimmune disease?

Answer 28

Lupus, rheumatoid arthritis, type one diabetes.

Question 29

What are antibodies?

Answer 29

Y-shaped glycoproteins. e.g: immunoglobulin

Question 30

What is the role of antibodies?

Answer 30

Agglutinins (agglutinate pathogens (clumping together)).
Anti-toxins (neutralising toxins on pathogens).
Prevent pathogens binding.
Opsonins (tag pathogens for phagocytosis (cause chemotaxis))

Question 31

What is the structure of an antibody?

Answer 31

Y-shaped structure with two heavy (long) polypeptide chains joined by disulphide bridges. Two light (short) polypeptide chains on either side. Antigen binding site (variable region) at the two tips of the Y.

Question 32

How do antibodies bind to antigens?

Answer 32

The antibody binding site is a variable region, with different specific shapes, complementary to different antigens.
The antigen binding site forms an antigen-antibody complex with the antigen.