The Anti-PTK7 (CCK-4) antibody (clone 188B) recognizes human protein tyrosine kinase-7 (PTK7). PTK7, also known as colon carcinoma kinase-4 (CCK-4), is a receptor protein tyrosine kinase (RPTK)-like molecule that contains a catalytically inactive tyrosine kinase domain.1,2 PTK7 was identified to be important for neural development as a regulator of planar cell polarity, being required for convergent extension movement and neural tube closure.3 Using the Anti-PTK7 (CCK-4) antibody, PTK7 expression was recently analyzed on blood and bone marrow cells. PTK7 was shown to be expressed on plasmacytoid dendritic cells, CD141 (BDCA-3)high type-2 myeloid dendritic cells, and CD34+ hematopoietic progenitor cells (HPCs). PTK7 was detected on early (CD34+ CD133+) and late (CD34+ CD133–) HPCs. In tonsils, PTK7 was also found on some T cells.
Human PBMCs were stained with Anti-PTK7-APC and CD303 (BDCA-2)-FITC, CD141 (BDCA-3)-PE, or CD34-FITC, respectively. Cells were analyzed by flow cytometry. Plasmacytoid dendritic cells (PDCs) are identified by CD303 (BDCA-2), type-2 myeloid dendritic cells (MDC2s) by CD141 (BDCA-3), and hematopoietic stem cells (HPCs) by CD34 expression.
Identification of PTK7+ CD303 (BDCA-2)+ PDCs
Identification of PTK7+ CD141 (BDCA-3)high MDC2s
Identification of PTK7+ CD34+ HPCs