The immune response

Define= The production of antibodies due to the introduction of a pathogen into the body. Involves:

1. Antigen presentation
2. Clonal selection (choosing the right shape antibody)
3. Clonal expansion (mitosis
4. Antibody production

Antigen= A foreign substance (usually a protein) to which lymphocytes respond

Antibody= An immunoglobulin (a specialized immune protein) produced because of the introduction of an antigen into the body, which posses the remarkable ability to combine with the very antigen that triggered its production. 

Structure:

Binding site= Bind attach to antigen
Disulphide bridge= Hold shape/ tertiary structure
Constant region= Attach/bind to phagocyte 
Hinge region= Allow molecule to bend/flex/bind with more than one pathogen 

How do they work?

1. Neutralisation-Antibodies covering the pathogen binding sites prevent the pathogen from binding to a host cell and entering the cell.

2. Agglutination-A large antibody can bind many pathogens together. The group of pathogens is too large to enter a host system.

Primary immune response:

• Involves naive B and T lymphocytes (but not the memory)
• Much slower and smaller than the secondary response

Secondary immune response:

• Much larger response (more antibodies secreted)
• Involves the B and T memory cells 
• Much faster due to the memory cells