what are antigens and antibodies
From Wikipedia, the free encyclopedia. In immunology, an antigen is a molecule capable of inducing an immune response on the part of the host organism, though sometimes antigens can be part of the host itself. In other words, an antigen is any substance that causes an immune system to produce antibodies against it.
Each antibody binds to a specific antigen; an interaction similar to a lock and key. An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein produced mainly by plasma cells that is used by the immune system to identify and neutralize pathogens such as bacteria and viruses.