Antigen
Antigens are "targeted" by antibodies. Each antibody is specifically produced by the immune system to match an antigen after cells in the immune system come into "contact" with it; this allows a precise identification or matching of the antigen and the initiation of a tailored response. The antibody is said to "match" the antigen in the sense that it can bind to it due to an adaptation in a region of the antibody; because of this, many different antibodies are produced, each able to bind a different antigen while sharing the same basic structure. In most cases, an adapted antibody can only react to and bind one specific antigen; in some instances, however, antibodies may cross-react and bind more than one antigen.
Cancer/testis antigen family 45, member a5
Cancer/testis antigen family 45, member A5 is a protein in humans that is encoded by the CT45A5 gene.
This gene represents one of a cluster of six similar genes located on the q arm of chromosome X. The genes in this cluster encode members of the cancer/testis (CT) family of antigens, and are distinct from other CT antigens. These antigens are thought to be novel therapeutic targets for human cancers. Alternative splicing results in multiple transcript variants. A related pseudogene has been identified on chromosome 5. [provided by RefSeq, May 2010].