Determination of leukotriene effects on human neutrophil chemotaxis in vitro by differential assessment of cell motility and polarity.

The effects of leukotriene (LT) B4 and D4 on the motility of human peripheral blood neutrophils were investigated employing a novel analytical method. Using the under-agarose technique, migration distance and vectorial orientation of neutrophils in response to selected LT concentrations were determined with the aid of digital image processing. Neutrophil polarization induced by a chemotactic gradient was very apparent even at fields taken adjacent to the cell seeding well where little directional cell motility had occurred. Thus, cell polarization appeared to be the earliest response to chemoattractive LTs. Cell motility occurred in a dose-dependent manner to LTB4 according to determination of the leading edge. LTD4 produced similar effects on neutrophil polarization and motility, but these occurred only at very high concentrations. These data support the view that vectorial orientation is a prerequisite for directional migration of cells and it is also feasible that these are separately regulated events. Furthermore, our studies confirm that LTB4 and, to a much lesser extent, LTD4 are chemotactic for human peripheral blood neutrophils.