Cellular recognition of foreign materials by Bombyx mori phagocytes: I. Immunocompetent cells

Though Bombyx mori larvae possess five types of hemocytes in the hemolymph, the granular cells play a key role as phagocytes and also participate in the early phase of encapsulation together with plasmacytes. In this sense, these two hemocytes are regarded as immunocompetent cells in B.mori. A granular cell can internalize a foreign material at least smaller than itself, even if unable to uptake the whole. This observation will be noted because granular cells are reported to release some chemotactic materials into the hemolymph after their breakdown when they attach to a large foreign surface. The size of foreign materials seems to be an important factor to determine the cell behaviors of phagocytosis or degranulation. These descriptions are summarized in Fig.22.