A raft technique for chemotaxis: a versatile method suitable for clinical studies.

We describe a raft technique for the study of chemotaxis which possesses a number of advantages over the use of chambers. Membranes are laid on pads soaked in chemotactic agent and cells are contained in plastic cups, which are inverted on to the membrane. This method gives results which are similar to those obtained in conventional vessels. It would seem well suited to comparative measurements of chemotaxis in clinical series, for it avoids the use of special chambers, minimises the number of membranes and their handling and more than one cell suspension can be placed on a membrane. In addition, the method is experimentally versatile: simple manipulations allow work with cells adherent to other surfaces, studies of the effect of substituting a new agent or of reversing the gradient during an experiment, migration against gravity, and of the effect of non-adherent cells on migrating cells.