Alzheimer amyloid precursor proteins (APP) are actively secreted by stimulated human peripheral mononuclear blood leucocytes (PMBLs). Induction of APP transcription, translation and secretion was observed with several T cell mitogens but was highest with phytohemagglutinin. The time course of induction is similar to that reported for IL-2 and IL-2 receptor. We suggest that APP may play an important role in the construction of the immunological network and the differentiation of T cells.
