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.
Adoptive cell transfer
Cancer-testis antigens are a family of intracellular proteins that are expressed during fetal development, but with little expression in normal adult tissues. More than 100 such molecules are epigenetically up-regulated in from 10 to 80% of cancer types. However, they lack high levels of protein expression. Approximately 10% of common cancers appear to express enough protein to be of interest for antitumor T cells. Low levels of some cancer-testes antigens are expressed in normal tissues, with associated toxicities. The NYESO-1 cancer-testes antigen has been targeted via a human TCR transduced into autologous cells. ORs were seen in 5 of 11 patients with metastatic melanoma and 4 of 6 patients with highly refractory synovial cell sarcoma.