BAIER: Now, does Secretary Clinton factor into this? SCHWEIZER: For that deal to go through, it needs federal government approval and one of those people that has to approve that deal is Secretary of State Hillary Clinton.
An antigen is any foreign substance which invades the body of an organism, while a pathogen is a living antigen (such as viruses or bacteria) which invade an organism. Many different kinds of white blood cells exist which are able to help the body fight foreign invaders in various ways.
The foreign substance, usually a protein, is called an antigen, that is, one that generates the production of an antagonist. The most common response to the antigen is the production of antibody. The antigen--antibody reaction is an essential component of the overall immune response. A second type of activity, cellular response, is also an essential component.