Clone REAL225 is an antibody fragment derived from the full CD303 (BDCA-2) 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.
CD303 (BDCA-2) antibodies have been used, for example, to identify, characterize, and enumerate plasmacytoid dendritic cells in whole blood of healthy and HIV-infected individuals, and for analyzing the role of DC-SIGN in HIV infection and transmission. Furthermore, CD303 (BDCA-2) antibodies were used to identify and enumerate plasmacytoid dendritic cells in blood and bone marrow samples before and after hematopoietic stem cell mobilization or transplantation. CD303 (BDCA-2) antibodies were also used for immunohistochemical staining, for example to identify plasmacytoid dendritic cells in tissue sections from patients with different inflammatory skin diseases.
Clone REAL225 recognizes the CD303 (BDCA-2) antigen which is expressed on human plasmacytoid dendritic cells in blood, lymphoid (e.g. tonsils and bone marrow), and non-lymphoid tissue. Specific expression allows direct identification of plasmacytoid dendritic cells using just one marker. CD303 (BDCA-2)+
plasmacytoid dendritic cells in blood and bone marrow are CD11c–
, CD304 (BDCA-4/Neuropilin-1)+
, CD141 (BDCA-3)low
, CD1c (BDCA-1)–
, and CD2–
. They express neither myeloid lineage markers (CD13, CD33) nor Fc receptors (CD32, CD64, FcRI). CD303 (BDCA-2) is strongly expressed on freshly isolated plasmacytoid dendritic cells but down-regulated within 48 hours of culturing. Unlike CD304 (BDCA-4/Neuropilin-1), CD303 (BDCA-2) is not detectable on ex vivo generated monocyte-derived or hematopoietic precursor cell-derived CD1a+
The CD303 (BDCA-2) antigen is a type II transmembrane C-type lectin. Remarkably, plasmacytoid dendritic cells can take up ligands via CD303 (BDCA-2), then process and present the ligands to T cells. Unlike binding of antibodies to CD304 (BDCA-4), binding of antibodies to CD303 (BDCA-2) inhibits type I interferon production, which is induced in plasmacytoid dendritic cells by, for example, the influenza virus.
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.