Direct Chemotaxis and Leucocyte‐Induced Chemotaxis of Polymorphonuclear Leucocytes

The present study was designed to discriminate and analyze the presence of direct PMN chemotaxis and leucocyte‐induced PMN chemotaxis in filter assay systems of PMN chemotaxis, namely the Wilkinson chamber and the Boyden chamber, which yield a more quantified information on leucocyte chemotaxis than filming of vital cells. The PMN chemotaxis was reduced by approximately 30–35 μm after incubation with vinblastine, 0.01, 0.10 and 1.00 μg/ml respectively, as measured by the leading front method in the Wilkinson chamber. This figure was thought to represent the contribution of the leucocyte‐induced antitubulin‐sensitive PMN chemotaxis to the casein‐induced PMN chemotaxis under the experimental conditions prevailing. The remaining 60 μm antitubulin‐insensitive PMN migration into the filter probably represented a combination of direct PMN chemotaxis and stimulated PMN random motility. Since the above‐mentioned vinblastine inhibition of PMN chemotaxis was recorded in the absence of serum, complement factors included, the vinblastine‐inhibited PMN chemotaxis was thought to be due to the release of a leucocyte‐derived cytotaxin. The significance of incubation time and chemotactic parameters was further analyzed in the presence of serum in Boyden chambers, in the intercompartmental filters by means of PMN distribution curves and on the bottom filter by cell numbers. The antitubulin inhibition of PMN chemotaxis was evident in the intercompartmental filter during the initial period of incubation and later by cell counts on the bottom filter. These observations suggested that the antitubulin inhibition of PMN chemotaxis was due to antitubulin inhibition of the direction‐finding in a minor proportion of fast‐moving PMNs.