UNIT 4 7D: The third line of defence

Question 1

Immunological memory

Answer 1

The ability of the immune system to quickly and specifically recognise an antigen that the body has previously encountered and initiate a corresponding immune response

Question 2

Clonal selection theory

Answer 2

The scientific theory that a specific antigen activates a specific lymphocyte that has a complementary receptor

Question 3

Naive

Answer 3

Not yet activated

Question 4

Antibody

Answer 4

A protein that has a Y shape containing two identical arms with an antigen-binding site specific to an antigen (or allergen); also referred to as immunoglobulins (lg)

Question 5

Clonal expansion

Answer 5

The proliferation of a lymphocyte that has been selected by an antigen

Question 6

What is the specific role of plasma B cells

Answer 6

To produce and secrete specific antibodies with the same antigen-binding site as the original cell surface antibody receptors on the original naive B cell.
They produce 2000 of these antibodies per second.

Question 7

Components of the humoral response

Answer 7

Naive B cells
Plasma B cells
Memory B cells
Antibodies

Question 8

Components of the Cell-mediated Response

Answer 8

Naive T cells
Memory T cells
Helper T calls
Cytotoxic T cells

Question 9

How would transplant rejection occur

Answer 9

Cytotoxic T cells or Natural killer cells can kill cells from transplanted tissue organs, as they have been identified as foreign/non-self, leading to transplant rejection

Question 10

Two functions of antibodies

Answer 10

1. Agglutination
   Clumps pathogens by binding to specific complementary antigens, allowing phagocytes to engulf more pathogens at once
2. Neutralisation
   Attaches to specific antigen and prevents it from entering a host cell

Question 11

How many types of antibodies are there

Answer 11

5
(IgG, IgE, IgD, IgM, IgA)

Question 12

Steps of the humoral response

Answer 12

1) Antigen of the pathogen is presented on MHC 2 of macrophage
2)Macrophage migrates to lymph node
3)Antigen-MHC complex activates a specific T Helper cell
4)T-Helper cell sends cytokines to activate a naive B cell
5)B cell proliferates into Plasma B cells and Memory B cells
6)Plasma B cell secretes specific Antibodies
7)Soluble antibodies enter the plasma of the bloodstream

Upon locating the specific pathogen(s), process will occur such as
1) Agglutination
Antibodies bind to pathogens and clump them together, allowing phagocytes to engulf multiple pathogens at once (increases efficiency of phagocytosis)
2) Neutralisation
Antibodies bind to pathogen and prevent it from entering a host cell(spreading/growth)

Question 13

Steps of the cell mediated response

Answer 13

1) Antigen of the pathogen is presented on MHC 2 of macrophage
2)Antigen-MHC complex activates a specific T helper cell
3)Cytotoxic T cell is created through T cell proliferation
4)Tc cells recognise infected host cells by antigen fragments presented on MHC 1 market
5)Complementary cytotoxic T cell receptor binds to an antigen
6)Tc cell will induce apoptosis 1 of 2 ways:
-Triggering caspase
- Activating a cell death receptor