CYTOPLASMIC MOTILITY REFLECTS PHAGOCYTIC-ACTIVITY IN ALVEOLAR MACROPHAGES FROM DOG LUNGS

To determine whether cytoplasmic motility relates to phagocytic activi ty of alveolar macrophages (AM), we measured the remanent field streng th (RFS) from the AM containing Fe3O4 particles (5 X 10(6) cells) and the number of phagocytized fluorescent latex spheres in the AM without having Fe3O4 particles (10(6) cells) harvested by broncho-alveolar la vage from dog lungs in vitro. Cytoplasmic motility was estimated from the relaxation rate (lambda(o); min(-1)) calculated from the decay cur ve of RFS and the number of phagocytized latex spheres was counted usi ng fluorescent microscopy after the addition of latex spheres (5 X 10( 7)). The tumor necrosis factor increased both lambda(o) and the number of phagocytized latex spheres, and cytochalasin D and colchicine decr eased them in a concentration-dependent fashion. Increases and decreas es in lambda(o) induced by drugs paralleled the number of phagocytized latex spheres. These results suggest that cytoplasmic motility reflec ts phagocytic activity of AM and both cytoplasmic movement and phagocy tosis may be regulated by a similar mechanism in the cytoskeletal syst em.