Antibodies

• Antibodies are proteins found in the blood or lymph that have the potential to be used as an immune defense against antigens, or agents that are foreign to the body. That antibodies and antigens are related, and that antibodies are made of protein, were both discovered by Michael Heidelberger in the 1920s and 1930s.
  
  

Neutralization

• Neutralizing antibodies are antibodies that can successfully prevent an antigen, usually a virus, from infecting a potential host cell by inhibiting its effect on the cell. One way to do this is by blocking the receptors of either the cell or the virus.
  
  

Vaccinations

• Neutralizing antibodies may be produced to protect against disease by exposing a person to small amounts of the antigen, thereby causing his immune system to produce the desired antibodies. If the host is thereafter exposed to the antigen, the antibodies produced by the vaccination will prevent the antigen from infecting her.