Neutrophil granulocyte chemotaxis in a reversible Boyden chamber

Abstract

The most widely used technique for measuring leukocyte chemotaxis in vitro is some modification of the method introduced by Boyden¹. This technique uses a chamber that is divided into two compartments by a membrane filter, the upper compartment containing the cells and the lower one containing the chemotactic agents. A concentration gradient is thus formed across the thickness of the membrane filter. The pore size of this filter is sufficiently small to prevent the cells from dropping through the filter, usually between 3 and 8 microns depending on the type of cells to be tested. During the incubation period the leukocytes migrate through the filter. The chemotactic activity can then be expressed either by the distance moved into the filter by the front line of cells or by the number of cells that have passed all the way through the filter and are lying on its attractant opposite surface. This method, however, has been reported to be inaccurate², since an unpredictable number of cells may detach from the filter after their arrival at its attractant surface. They will thus elude enumeration and the result will be falsely low.