MHC-restricted antigen recognition, or MHC restriction, refers to the fact that a T cell can interact with a self-major histocompatibility complex molecule and a foreign peptide bound to it, but will only respond to the antigen when it is bound to a particular MHC molecule.

MHC class I molecules are one of two primary classes of major histocompatibility complex molecules (the other being MHC class II) and are found on the cell surface of all nucleated cells in the bodies of vertebrates.

MHC Class II molecules are a class of major histocompatibility complex molecules normally found only on professional antigen-presenting cells such as dendritic cells, macrophages, some endothelial cells, thymic epithelial cells, and B cells.

a group of proteins belonging the class of major histocompatibility complex.