Source:http://linkedlifedata.com/resource/umls/id/C1515144
NCI: Any process in which a specific pair of interactions is observed between a T cell and an antigen-presenting cell, where the interactions include those between the T cell receptor and the major histocompatibility complex and those between CD28 and B7 family members. This process is involved in anergy and specification of the immune response to a particular antigen.