12.6 Specific Immune System

Question 1

What’s an advantage and disadvantage of the specific immune response (active/acquired immune response)

Answer 1

advantage: if the same pathogen enters the body again, the body is really quick at responding with memory cells
disadvantage: it can take up to 14 days for the first response to battle the pathogen

Question 2

What’s the structure of antibodies

Answer 2

y-shaped glycoproteins called immunoglobulins; these bind to a specific antigen on a pathogen;
2 identical polypeptide chains known as HEAVY chains and 2 LIGHT chains held by disulphide bridges;
antibodies bind to proteins with a ‘lock and key’ mechanism;
binding site is 110 amino acids on the heavy and light chains (called VARIABLE region);
hinger region allows antibody to be flexible so it can bind to 2 antigens.

Question 3

through what 3 ways do antibodies defend the body

Answer 3

1. neutralisation
2. acting as anti-toxins
3. agglutination

Question 4

what’s neutralisation

Answer 4

antibodies called anti-toxins can bind to toxins produced by pathogens; this prevents the toxins affecting human cells, so toxins are neutralised.

Question 5

what’s agglutination

Answer 5

each antibody has 2 binding sites so can bind to 2 pathogens; the pathogens become clumped together. Phagocytes can then phagocytose the pathogens at once. Antibodies that do this are known as agglutinins.

Question 6

How do antibodies prevent pathogens binding to human cells

Answer 6

antibodies bind to antigens on pathogens so they may block the cell surface receptors the pathogen needs to bind to the human cell. The pathogen can’t bind to host cells as a result.

Question 7

What’s the 2 different of lymphocytes

Answer 7

T lymphocytes (mature in Thymus gland) and B lymphocytes (mature in bone marrow)

Question 8

What are the types of T lymphocytes

Answer 8

killer, memory, helper, regulator

Question 9

what do T killer lymphocytes do

Answer 9

produce perforin which perforates the pathogen, therefore, destroying it

Question 10

what do T memory lymphocytes do

Answer 10

if they meet the same pathogen again, it rapidly divides to form T killer cells

Question 11

what do T regulator cells do

Answer 11

ensures the body recognises ‘self’ antigens; prevents autoimmune response

Question 12

what do T helper cells do

Answer 12

they have CD4 receptors which bind to antigens on APCs; produce interleukins (type of cytokines) to act as a signalling molecule.

Question 13

what are examples of B lymphocytes

Answer 13

effector, memory, plasma cells

Question 14

What do B memory lymphocytes do

Answer 14

immunological response; rapid response when a similar or same pathogen is encountered a second time

Question 15

what do plasma cells do

Answer 15

produce antibodies for a certain antigen/pathogen; can produce 2000 a second into the bloodstream

Question 16

what do B effector cells do

Answer 16

divide to form plasma cell clones

Question 17

what are the 2 types of specific response the immune system can produce

Answer 17

cell mediated and humoral

Question 18

what’s cell mediated immunity and what does it fight against

Answer 18

involves highly specialised cells that target pathogens inside cells. Fights infections and early cancers. Where T-lymphocytes respond to cells in an organism that have changed in some way

Question 19

What do T-lymp. do in cell mediated immunity

Answer 19

it has receptors on its surface which bind to antigens presented by APCs when they have complementary shapes; this activates the T-lymp.

Question 20

What’s the process of cell mediated immunity

Answer 20

1. (from non specific response) macrophages engulf and digest pathogens in phagocytosis, process the antigens from the surface to from APCs.
2. receptors on some of the T helper cells fit the antigens; these produce interleukins, stimulates T cells to divide; from identical clones to carry same antigen to bind to pathogen.
3. the cloned T cells may:
   - develop into T memory cells
   - produce interleukins for phagocytosis/B cells to divide
   - develop T killer cells

Question 21

What do cloned T-lymphocytes do in cell mediated immunity

Answer 21

they may:

1. develop into T memory cells
2. produce interleukins to stimulate phagocytosis
3. produce interleukins to stimulate B cells to divide
4. stimulate T killer cell development

Question 22

what’s humoral immunity

Answer 22

response targets pathogens in the body fluids with antibodies on the surface of B-lymphocytes.
When there’s a pathogen complementary to a B-cell antibody, it will engulf it and become an APC.

Question 23

What is clonal selection in humoral immunity (pt. 1 of humoral process)

Answer 23

A T-helper cell will bind to the B cell APC; at this point the correct antibody is selected for cloning

Question 24

What’s clonal expansion (pt. 2 of humoral process)

Answer 24

Interleukins produced by the activated T helper cells activate B cells; these B cells replicate through mitosis to make clones of plasma cells (with the correct antibody) and B memory cells

Question 25

What is the primary and secondary immune response (pt. 3 & 4 of humoral response)

Answer 25

Primary: cloned plasma cells produce antibodies that fit the antigens on the pathogen and disable them (agglutinins/opsonins).

Secondary: cloned B cells develop into B memory cells so if the pathogen reoccurs, the body will be quicker at responding with the correct antibody.

Question 26

What is an autoimmune disease

Answer 26

When the immune system stops recognising ‘self’ cells and starts to attack healthy body tissue. Can be genetic, or a mild pathogen not being treated properly, T regulator cells not working effectively.
Treatments may be immunosuppressants but they deprive natural body defences.
Examples include type 1 diabetes, lupus