T-Cell Receptors

The cell surface of a T lymphocyte contains receptormolecules
that with high specifity recognize
foreign antigens and cell surface molecules
of theMHCcomplex. The T-cell antigen receptor
(TCR) consists of a complex of several integral
plasma membrane proteins. Unlike B cells, T
cells recognize only fragments of foreign antigen
proteins. In addition, they bind physically
to the MHC complex of an antigen-presenting
cell. During maturation of the T cells in the thymus,
T-cell gene segments are rearranged in a
defined order by somatic recombination, similarly
to the formation of immunoglobulins.