MIGRATION OF HUMAN GRANULOCYTES IN FILTERS - EFFECTS OF GRAVITY AND MOVABLE GRADIENTS OF F-MLP

The Boyden chamber technique for chemotaxis uses a mesh filter that co nstitutes a matrix for cell locomotion and, at the same time, creates a local restriction for convective fluid movements that allows the est ablishment of a diffusive concentration gradient of chemotactic substa nce in the filter. In the present study, the Boyden chamber was modifi ed by the introduction of a filter sandwich that allowed cell migratio n both upwards and downwards and by the use of a fluid density gradien t controlling cell buoyancy and mechanically supporting a movable chem otactic gradient, This method was used to study chemotaxis and random migration of human granulocytes under the influence of gravitational f orces and movable gradients of f-MLP. The results show that gravity af fected cell motion significantly during random migration but not durin g chemotaxis, The rate of chemotactic migration was dependent on the s teepness of the spatio-temporal f-MLP gradients, A stationary spatial gradient produced less migration than a gradient that was slowly moved through the filter sandwich in a direction opposite to that of the Th e presence of f-MLP at constant concentration caused a minor, statisti cally insignificant, increase of the rate of random migration.