Tools for analysis of cell adhesion molecules under physiological and pathological conditions

The adhesion of circulating leukocytes to the luminal surface of the microvasculature is important for their recirculation and inflammatory response. The key adhesion molecules for initiating such interactions are CD44 and selectins. To investigate the roles of these molecules in the blood vessels, we reconstituted the defined fluid flow in the microvasculature under a microscope, and analyzed the cell dynamics on various substrates. Using this system, we found that CD44 functions as a rolling receptor for chondroitin sulfates under physiological flow conditions in addition to a well-known ligand, hyaluronan. P-selectin also mediated cell rolling by interacting with a physiological ligand glycoprotein under such conditions. We also developed a sensitive enzyme-linked immunosorbent assay system to measure P-selectin, and show that P-selectin in the blood could serve as a sensitive biomarker reflecting lung inflammation.