In vitro evidence for the requirement of filopodial elongation for the progress of phagocytosis by phagocytic granular cells of the silkworm, Bombyx mori.

The significance of filopodial elongation of phagocytic granular cells of Bombyx mori in the progress of phagocytosis was investigated by regulating the degree of filopodial elongation with low temperature and cytochalasin B (CB). Elongation-inhibited cells were unable to ingest foreign cells such as sheep erythrocytes (SRBC), while cells having more or less the ability to elongate their filopodia against SRBC could phagocytose them. The results showed that filopodial elongation was an essential element in the progress of a series of phagocytic processes following attachment, and also suggested that certain level of intracellular phagocytic signals obtained during elongation is required for the completion of phagocytosis.