Improvements to parallel plate flow chambers to reduce reagent and cellular requirements

In this study, we evaluate modifications to a newer parallel plate flow chamber design in comparison to the original parallel plate flow chamber described by Lawrence et al. We show that modifications in the chamber size, internal tubing diameters, injection valves, and a recirculation design may dramatically reduce the cellular and reagent requirements without altering measurements.These modifications are simple and easily implemented so that study of rare leukocyte subsets using scarce or expensive reagents can occur.Localization of leukocytes to tissue sites is a critical part of infectious, inflammatory or immune responses [1,2]. Emigration of leukocytes from blood into tissue requires a complex array of molecular and cellular events between the flowing leukocyte and endothelium lining the blood vessel wall. Development of the parallel plate flow chamber that simulates the conditions of physiologic flow has been an important tool for dissecting the molecular events occurring between flowing leukocytes and endothelium [3-13].One of the first parallel plate flow chamber described to study neutrophil adhesion to endothelium was described in 1987 by Lawrence et al [7]. Initially, several investigators produced chambers identical to or very similar to this design, and over the years this initial design has been the most widely used [8]. This design allowed for study of leukocyte-endothelial interaction from a top-down view and under laminar flow that occurs in the post-capillary venules, the physiologically relevant site for most leukocyte emigration. Design modifications have also been made that allow for pulsatile flow, a simulation of larger vessel blood flow, as well as lateral viewing that can give more detailed morphologic information [11,12]. Agarose-cast vessels and glass capillary flow chambers have also been described [12,14,15]. In spite of the large number of scientifically important observations that have been made with this technology, these chambers ha