PV-1 is recognized by the PAL-E antibody and forms complexes with NRP-1

Area of Science:

• Vascular biology
• Immunohistochemistry
• Molecular cell biology

Background:

• The Pathological Anatomy Leiden Endothelium (PAL-E) antibody is a long-standing marker for vascular endothelium.
• Its precise molecular target has been debated, with plasmalemma vesicle-associated protein-1 (PV-1) and neuropilin-1 (NRP-1) being proposed candidates.

Purpose of the Study:

• To definitively identify the molecular target of the PAL-E antibody.
• To investigate the relationship between PV-1 and NRP-1 in endothelial cells.

Main Methods:

• Immunofluorescence staining in various tissues.
• Flow cytometry analysis of transfected cells.
• Western blotting and co-immunoprecipitation assays using tissue and cell lysates.

Main Results:

• PAL-E and anti-PV-1 antibodies exhibited identical staining patterns to anti-CD31 and anti-NRP-1 antibodies in tissues.
• PV-1-transfected cells bound PAL-E and anti-PV-1, while NRP-1 transfectants bound anti-NRP-1.
• PAL-E and anti-PV-1 antibodies recognize PV-1, not NRP-1.
• NRP-1 and PV-1 were shown to form molecular complexes.

Conclusions:

• The PAL-E antibody specifically recognizes PV-1.
• NRP-1 and PV-1 interact, forming complexes relevant to leukocyte trafficking and angiogenesis.
• This interaction opens new avenues for research in endothelial cell biology and related pathologies.