Specific Immune System

Question 1

How do antibodies defend the body

Answer 1

• antigen binds to antigen binding site of antibody and acts as an opsonin so antigen easily engulfed
• antibodies act as agglutanins and cause pathogens to clump together preventing them to spread throughout the body
• act as antitoxins binding to toxins to make then harmful

Question 2

T Lymphocytes

Answer 2

• t helper cells - have receptors on their membrane which binds to surface antigens and produce cytokines to stimulate b cells
• t killer cells - destroy pathogen carrying the antigen and produce performing which pierces the membrane so its freely permeable
• t memory cells- secondary response and divides rapidly to form t killer cells that destroy pathogen
• t regulator cells- suppress the immune system and stop immune response once pathogen eliminate

Question 3

B lymphocytes

Answer 3

• when b cells activated by t helper cells:
• divide by mitosis into plasma cells and further into antibodies.
• b effector cells- divides to form plasma cell clones
• b memory cells- remain in blood for long time for secondary response to allow rapid response to antigens and produce specific antibody

Question 4

Cel mediated immunity ( after phagocytosis)

Answer 4

1) the t helper cells receptor fits the antigen presenting cells on phagocyte and become activated to produce interleukins

2) interleukins stimulate more T cells to divide rapidly by mitosis into plasma

3) they form clones of T helper cells with specific antigen to bind to pathogen

4) the cloned T cells may either:
- develop into t memory cells
-produce cytokines for b cells
- stimulate t killer cells
- stimulate phagocytosis

Question 5

Humoral immunity (produces antibodies that are soluble in blood)

Answer 5

1) as activated t helper cells bind to b cell antigen presenting cell, this is clonal selection where the b cel with correct antibody is selected for

2) interleukins produced b active T cells activate b cells

3) activated b cels divide by mitosis into plasma cells and b memory cells which is clonal expansion where

4) cloned plasma cels produce antibodies that fit antigen on surface of pathogen to act as oppsonins or agglutanins

5) some cloned b cels develop into b memory cells which remain in blood for long time and if body infected by same pathogen, b memory cells rapidly divide by mitosis into plasma cells to produce specific antibodies to wipe out pathogen very quickly