Microfluidic platform simulation of leucocyte adhesion to the endothelium (97.8)

Abstract Leukocyte adhesion to endothelial cell bound proteins, such as ICAM-1 and VCAM-1, is an initial step of the inflammatory response. We have developed an in vitro microfluidic system which mimics conditions found in blood vessels in vivo during an immune response. Using this system, we can record leukocyte adhesion levels under physiologically relevant flow conditions (e.g. 0–5 dynes/cm2). The adhesion profiles of resting and PMA-stimulated peripheral blood lymphocytes (PBLs) were recorded, with respect to VCAM-1, ICAM-1, and BSA. Images at each shear stress level were captured using a digital camera, and analysed using our in-house Ducocell software package. Distinct morphological changes in PMA-stimulated PBLs, compared to non-stimulated cells, can be observed. These include a less rounded appearance of the PMA-stimulated PBLs, and evidence of “uropod” formation, which anchor the T cell to the endothelium as part of the migration process. Levels of adhesion to VCAM-1 are high (80–90%, compared to control), but there appears to be little difference between the adhesion profiles of non-stimulated and PMA-stimulated PBLs. However, there is a distinct difference between the adhesion levels of non-stimulated and PMA-stimulated PBLs to ICAM-1, with PMA-stimulated cells showing a higher affinity for ICAM-1 than non-stimulated cells (approx. 70% and 40%, respectively). PBL adhesion to BSA is negligible.