Allorecognition by T cells

Alloreactive T cells may recognize incompatible MHC molecules directly on the stimulator antigen presenting cells (APC or dendritic cell) or indirectly after processing by a responder or histocompatible stimulator APC. Usually, the APC migrates to lymph nodes where the encounter with T cells occurs.

After activation, effector T cells recognize the incompatible molecules against which they have been primed and attack foreign tissues.

Recognition of incompatible tissue by T cells

Throughout the movies on allorecognition, proteins (MHC molecules as well as other polymorphic proteins of which the peptides are presented by the MHC-molecules) that differ between responder and stimulator will be depicted in red, while autologous proteins or proteins that are identical in the stimulator are depicted in blue.

autologous
mismatched, allogeneic

Read (much) more about direct / indirect pathway allorecognition by T cells or priming.