Neutrophilic leukocytes in immunologic reactions in vitro: effect of cytochalasin B.

Neutrophilic leukocytes (neutrophils) participate in immunologic tissue injury through the extracellular release of pro-inflammatory lysosomal bioactive factors (1). The translocation of lysosomes and the selective extrusion of their contents occur in response to phagocytizable (2, 3) and non-phagocytizable immune complexes (4, 5). It has been observed recently that cytochalasin B inhibits phagocytosis in neutrophils (6) as well as a number of other cellular functions apparently dependent on the microfilament system (7, 8). Since phagocytosis and lysosomal release have been clearly linked in the neutrophil the possibility that cytochalasin B might modulate this release reaction was investigated. The effect of cytochalasin B on the closely related if not identical process of non-phagocytic immune complex induced lysosomal release was examined concurrently. Neutrophilic leukocytes were isolated from rabbit peripheral blood as described previously (2). Polystyrene latex particles (Dow Chemical Co., Don Mills, Ontario), 1.10 nm in diameter, were coated with rabbit γ globulin (RGG)2 and employed as the phagocytizable particles.