Clone REAL383 is an antibody fragment derived from the full CD279 (PD1) antibody molecule. It displays no binding to Fc receptors. The recombinantly engineered antibody fragments are multimerized to form the REAlease Complex to bind markers with high avidity.

Clone REAL383 recognizes the human CD279 antigen, also known as PD-1 (programmed death-1) or PD1. CD279 is a 55 kDa transmembran protein belonging to the CD28/CTLA-4 family. It is expressed on T cells, B cells, NK cells, activated myeloid cells, and dendritic cells. CD279 is not expressed on naive T cells but induced after activation and expressed on late, differentiated T cells. The ligands PD-L1 (CD274, also knwon as B7-H1) and PD-L2 (CD273, also known as B7-DC) belong to the B7 immunglobulin superfamily. PD-1 and its ligands mediate inhibitory signals that regulate the balance between T cell activation, tolerance, and immunopathology.

The REAlease Kits consist of the respective fluorochrome-conjugated REAlease Complexes and the REAlease Support Kit for removal of the REAlease Complexes and optional relabeling with different fluorochrome-conjugated REAlease Complexes.